agp440.sys and dead XP system

I recently had my system apparently die on me and wanted to share the symptoms and the apparent cause in case anybody else comes across this issue.


  • Tried to reboot my computer (first a warm reboot – restart, then a cold reboot – shutdown, wait, power up again) saw the POST (power on self Test) then saw the initial Windows logo with the little animated “runner marquee” at the bottom. Then this cleared and… nothing. What should have happened next was that my blue XP “Click your username to login” screen should have appeared. I needed to kill power to my PC in order to do anything in both cases.
  • Then resorted to starting up in Safe mode – in XP you don’t even need to fiddle with the F8 key, you are presented with this option if the system detects a failed startup attempt – simplifies things. When starting in safe mode you get to see all of the drivers being listed as they are loaded. And each time I attempted this (I tried a couple of times) the last driver loaded was agp440.sys.

So you know the environment that I am using to know if the solution below is relevant to you:

  • Powerspec 8922 – from Microcenter
  • 2.6 GHz Pentium 4 processor (with HT technology)
  • 1 Gbyte of RAM (upgraded from default 512 Mbytes)
  • 120 Gbyte 7200 rpm ATA/133 Hard Drive
  • ATI (VisionTek) XTASY 9600 graphics card (to drive dual monitor configuration)
  • Belkin USB 2.0 hub
  • Windows XP Home edition – with SP2 applied
  • SanDisk Cruzer Mini USB 1 Gbyte Thumb drive

That’s everything that’s relevant to this issue – of course there is the usually panoply of routers, monitors and other USB devices.

I grabbed my wife’s laptop and did some Google searches on agp440.sys and found that this appears to be a red herring. I believe it just happens to be the last of the drivers loaded before services start being initiated.
Several folks did some experiments where they renamed or otherwise disabled the agp440.sys driver and found that the failure then occurred on the next previous driver.

Someone then mentioned that they disconnected their USB mouse and things seemed to work after that for them. Others mentioned that they had to perform chkdsks which found and corrected bad sector info on their hard drives.

Anyway, I had plugged my thumb drive into the computer to check some stuff a while ago and hadn’t bothered to remove it.
I had just shut down the computer and then turned off the power to my USB hub, routers and modem as I wanted to reset them. I did this by powering off my UPS. I suspect this was a harsh shutdown for the thumb drive, even though it was not talking to the computer anymore.
With my computer in safe mode just sitting at the agp440.sys I reached over and just yanked out the thumb drive. *Presto* the computer then continued to boot up in safe mode.

Apparently there was some issue initializing the thumb drive and as long as it was plugged into my usb hub I wasn’t going to be using my computer any time soon.

In safe mode I instructed the system to do a chkdsk /R on my only drive (C:) and then restarted. Cannot get a lock on the primary partition’s NTFS formatted disk after the OS has been set up.

WOW! It takes a long time to chkdsk a 120 MByte drive when about 70 Gbytes are in use… expect this to take a couple of hours at least.

Anyway I let that run overnight and in the morning everything was right as rain.

Later I inspected my thumb drive – hmmm… no problems here. Even did a chkdsk on it (not sure how relevant that is…). But I can only surmise that there was some inconsistency caused by the harsh shut down of the thumb drive.

Hopefully this information can be useful to other people who encounter this issue.

30 thoughts on “agp440.sys and dead XP system”

  1. Hi, same problem here on two Dell’s. NTFS.sys is the sys file that loads immediately PRIOR to the stop on AGP440. What about you? Agreed, the AGP440 issue is a red herring. So, are you now using the same USB devices with no problem? Thanks!

  2. Yes, once I yanked the USB thumbdrive everything was absolutely fine.

    Admittedly I no longer leave the thumb drive in when I’m rebooting (shouldn’t have been doing that anyway – it *should* be in my pocket available for use). But I have plugged it into the hub again, same port, and read and wrote to it with no problems.

    However I cannot say that it was necessarily just a temporary glitch. The overnight chkdsk could have also resolved some issues ‘though it reported nothing alarming (no bad sectors, just cleaned up a bunch of unused index entries and security descriptors).

    Not much help for you it seems, but in my case I think it boiled down to a bad chain that just needed one link removed.

  3. I’ll keep this short and simple, but I basically got the whole hang up things as well. P4 2.2 gig, running XP Pro.

    After pouring thru hundreds of posts on over a dozen sites, I found one common sliver, mass storage devices, i.e. USB drives and the like.

    Well, in the midst of my rage at not being able to fix my damn computer, I noticed that my CF card was inserted into the reader. Pulled the frickin’ thing out and the computer booted like it was brand new.

    Damn I hate computers every now and then.

  4. .: I experienced this agp440.sys problem tonight. I surfed the net on my laptop trying to find a solution, and came across yours. My error happened after I installed the software for a Maxtor 320GB drive. After installation, I connected the drive via a USB port, and shortly thereafter everthing collapsed. The Maxtor wants to use a USB 2.0 port, but the Dell Dimension 4400 only has 1.0 ports, so I wonder if that caused the problem. However, I’ve used a 160GB external drive on the Dell before and didn’t have any problems with it.

    In any event, I am stuck. I’ve disconnected all other USB devices, and the Dell still hangs up at the damn agp440.sys file. I may need to bring the computer in to a repair shop, backup the drive, and reinstall Windows…

  5. I had the same problem 3 or 4 days ago. My digital camera was connected to the laptop and turned on. I was downloading photos from it. When I opened a RAW file the OS hung. The only thing was to reboot by holding down the power button.

    The following boot was fatal.. BSOD (stating “UNBOOTABLE_…”) and/or stopping a the agp440.sys depending on the chosen setting. My Linux install worked file and I could see all the files, though reding the NTFS partition was slower than usual. After trying out everything, but voodoo dolls and chanting from withing the Linux install, I am now running the CHKDISK /r… I will write more after it finishes…

  6. Thank you very much for your advice, it worked perfectly!!

    Anyway, after I finish my A-levels I will never use windows again (I had to use it for running VB for my computing coursework).. it is too unreliable for storing my photos and work.

    Thanks again! =)

  7. I had this problem today when my system crashed while a flash drive was attached to the USB. I didn’t realize it was attached. Every time I rebooted, the system hung at the agp440.sys . As soon as I removed the flash drive, it booted up just fine!!

  8. I too had the same problem, and unplugging the USB devices fixed it. Thanks for posting. 🙂

  9. I recently purchased a new flat panel monitor with USB 2.0 hub built in. In the process of connecting it and configuring it, I disconnected the USB 1.1 hub which had a label printer, ink jet printer attached. I did this to clear the desk and make room for the new monitor. I then connected these printers directly to the computer and went about configuring the new LCD monitor. Upon reboot after loading video drivers I got the agp440.sys hang. I too thought this was a red herring, but began troubleshooting the hang. I even reloaded windows (which cleaned up a bunch of other problems) but still got the hang. I new this wasn’t hardware because the OS loaded. CPU and memory issues will surface quickly when decompressing cab files. I wasn’t sure what to do and wasted a whole day. All this for attaching a new monitor???

    So I started searching google and found all of the Microsoft KB references and a couple others that mentioned dead peripherals, such as CD/DVD. I had even wondered about the motherboard. Then I came across your post. I went home after work and disconnected all of the USB cables from the computer. It booted immediately to windows! I put the USB 1.1 hub back in place with the label printer and inkjet. I now know it was having the label printer attached directly that hung the computer at boot. It’s a great printer, so I blame Microsoft for not starting those services after windows loads.



  10. You’re welcome! I’m so glad that my own problem and troubleshooting can be of use to other folks!

    It’s an oddball issue that is such a SIMPLE solution, but only if you know what it is. 🙂

  11. Good day,

    Sounds like the computer you are using are trying to boot from the USB devices also it would also help to got into the BIOS and look for the USB listing and change the property to no boot so the computer would skip the USB ports when booting. Once this is done the computer should boot normally even if you leave the any USB device plugged in such as printers and thumb drives. Just want to raise my mind on the isseu

    Hope this helps.

  12. Hi,

    I had the same problem but I didn’t have any USB devices hooked up at the time the hang up occurred. I fixed it by unplugging my wireless Internet card and restarting. It booted up fine so I plugged my wireless card back in and restarted again and now it works fine with the card in it… totally weird. If anyone ever comes across the reason why this happens I’d be interested to hear it.

  13. My Powerspec 6644 would not boot. It would get stuck at login w/ no keyboard or mouse support. I replaced the replacment usb mouse and keyboard with the original non usb keyboard and mouse and pc worked fine. I think the USB hub died. Will look into replacing it tomorrow.

  14. I’ve tried everything you have listed, I have no USB plug ins, no networking cables of any kind, all i have plugged in is my monitor, my standard port Keyboard and mous, and my speaker. I’m still getting hung up at the agp440. It hang sup there, when i reboot it gives me the “run in safe mode” “run in safe mode with networking” “run with safe mode with command prompt” “load from last working configuration” “start windows regularly” and each one eiether brings me right back to the safe mode prompt, or gets hung up on agp440.

    I’m at a loss.

  15. Hi Marc!

    Thanks for the solution! I have an older Gateway laptop with XP and after I downloaded and installed my internet connection was dropped. When I restarted the machine, it hung. I found the boot stopped on the agp440.sys file. Did a Google search on the file which eventually brought me to your posting.

    I didn’t have a USB device plugged in, but I did have a wireless card plugged in. I pulled it out and started the machine, it started up!

    Thanks again, you have save me time and a machine. It’s about 5 years old and I was thinking of recycling it.

  16. Hey Fran,

    Thanks for posting your solution here too! That will hopefully help other folks who come here with similar symptoms.

    I’m glad you’ll be able to nurse a little more life out of your laptop!


  17. Thanks for this, I had the same problem and fixed it by unplugging my iPod. I had even tried putting in my Windows installation disc and it froze up doing that too.

  18. I tried everything! I Just can’t get my system to work! All i have plugged in are power cable, keyboard, and monitor! I unpluged both my cd-rom drives and made ms-dos boot disks that require botting of windows i guess! I EVEN PUT IN A NEW VIDEO CARD! Nothing at all works!!!!

  19. I’ve had the same problem on two different machines now; the latest being a laptop with nothing but a power cord plugged into it. It has only been used to watch DVDs for the last eight months. Nothing new installed and yet today it starts acting up.

    I tried the reverse of what you suggested and plugged in a USB hard drive. It actually booted up fine once I had done this. Of course it blue screened again later but I thought I would mention this as an option for others just in case it gets them past the problem point.

  20. Ok all.

    Very helpful thread and certainly can help quite a bit.

    I will post my solution to this issue to benefit as well.

    Same issue, system rebooted continuously after boss replaced her cmos battery.

    BIOS changed to disable Palate Snoop, USB and VGA IRQ had no impact.

    Popped out the battery, no impact.

    Swapped the AGP card for a PCI one, no impact.

    Booted to Recovery console per microsoft
    Disabled agp440 , no impact.

    Booted to recovery console and ran chkdsk /r which found errors and fixed them. System then booted into OS as expected. System did throw a message on having restored a registry value (the one disabled per the MS KB article)

    Shutdown system

    Reinstalled battery (while off, but plugged in) Swapped the Video cards back out and rebooted but could not use mouse. Restarted to change BIOS back to allow USB support, PaleteSnoop and IRG for VGA and got my mouse working. Yellow bang in Device manager indicated issue with AGP being disabled, so rebooted to Recovery Console to back out MS KB article changes. In the article, disabling is spelled out, but not re-enabling.

    To re-enable, the command is ENABLE AGP440 SERVICE_AUTO_START (note, there is a space between enable and agp440 and another between agp440 and service)
    Hit enter and then type exit to reboot.

    Caveat!! I changed from the c:\windows prompt to c:\ Whether this matters or not, I am not sure.

    Now everything is fine. Boss is happy.

    I hope this is helpful to someone.


  21. Thank you for this. I was looking at having to either replace my hard drive or buy a new computer – for the second time in exactly a month (Friday the 13th both times – making me superstitious!). Anyway, unplugged my USB tablet, rebooted into Safe Mode which I couldn’t do prior to unplugging the tablet, looked around on my computer and just exited normally. Booted up again into normal mode and everything was fine and dandy. Life is good. Mind you, I’m saving for a new computer but if this trick can get me by until then, I’m a happy camper. Thank you so much for posting and for everyone else’s input as well – I just saved some ching.

  22. Thanks for your feedback Dawn. It’s always nice to know that the effort of document a solution that I had issues resolving is helpful to other folks out there.

  23. @Marc – Marc, I just have to provide an update to my post yesterday. Not only did it fix the issue for my problem yesterday, it also fixed it for my previous drive AND the drive I had replaced 2 years ago!! I had suspected my USB ports were having an issue then, but it wasn’t anything consistent and all the research turned up zilch. At least I have my all of my data usable again for which I’m very thankful.

    Now I just have to figure out what causes the initial problem and fix that 🙂 That and save up for a MacBook Pro.

    Thanks again for having documented this issue and providing your solution. GREATLY appreciated!!!

  24. I had the agp440.sys problem. From past experience the first thing I tried was to re-seat all the expansion cards (i.e remove-and-reinsert). When that failed I tried removing all the expansion cards except my graphics card. But, still no luck. Finally, I removed the hard drive and used a usb-to-ide cable to connect it to another computer. When doing this I needed to remove the jummper on the harddrive (the jumper was on cs-select). Once the hard drive was connected as a usb mass storage device I ran:

    F:\>chkdsk f: /r

    In the out put of the chkdsk command I saw: “Windows replaced bad clusters in file 3290 of name \WINDOWS\system32\config\software.”

    After that I put back the jumper on the hard drive and re-inserted it in the pc that was previously failing to boot. I held my breath as I waited to see if it would get past the loading of agp440.sys. Luckily it did. Problem solved.

  25. Thank you Marc!
    My HP media center XP was hanging up after post, in safe mode I saw agp440.sys was last to load and found your note while looking for clues. The USB was it for me also, though not a thumb drive, it was the usb mouse, specifically, it halted the boot depending in which usb port it was connected to, most were ok, one was not.
    So thanks for getting me to look at usb before going into a OS repair.

  26. i had the same issue on a friends computer.. spent two days trying different things (ie. reseating everything, replacing video cards, among other things).. finally gave up and did a google search on the agp440.sys error.. found this post.. thought to myself, it couldnt be that easy to fix.. Sure enough, I rechecked the bios settings, the comp was set to boot from the cd drives first, then the hard drive. so i checked the cd drives.. found an AUDIO CD in it.. pulled the cd out, reset boot order in the bios.. and the computer has been booting perfectly ever since. Muchly appreciated on posting this!!!!

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