When replacing my new Iwill xp333r motherboard, I got an especially cryptic blue screen of death from Windows XP SP1:

STOP C0000415: Unknown Hard Error

After searching the microsoft knowledge base and google, I couldn't find any information about this particular error. I called ATI (the manufacturer of my video card), and they said that the problem was due to a corrupted AGP driver. Below are the steps necessary for me to fix the STOP error. I'm putting them on the Web in the hopes that the next person who gets this error will find this page.

• Etiology: Apparently, this error occurs mainly to ATI video cards (Radeon 8500, 9000, etc.) on SiS Athlon chipsets (Iwill). Although the error is reported in the Video driver, it originates in corrupted AGP drivers.
• How I fixed it:
  1. Reset computer. At boot screen, type 'f8' and select 'VGA mode'. You can also choose 'Safe mode' or 'Safe Mode w/Networking' but VGA Mode is the most powerful and will give you access to the Internet.
  2. If the system boots into XP ok, continue on. If not, then your problem is different than mine. Try ATI tech support.
  3. In VGA Mode, do the following:
     1. Go to 'Add/Remove Programs' in the Control Panel.
     2. Remove everything related to your video card. For ATI cards, be sure to remove the Control Panel and the Display Driver.
     3. Remove everything that looks like 'AGP Driver' or somesuch.
     4. Go to Control Panel -> System -> Hardware -> Device Manager.
     5. Open up the 'Display Adapter' folder, right click on your video card and open 'Properties'. It should say something about wanting to uninstall the driver when you restart. If not, right- click again and select 'Uninstall'.
     6. Reboot
  4. This time, allow the computer to reboot normally. If it doesn't come up normally, then I don't know what the problem is.
  5. Important: Apparently, XP does not fully uninstall the AGP drivers, so if you uninstalled a driver in step 3, you must reinstall it now before you reinstall the video card drivers.
  6. After re-installing the AGP driver, try reinstalling the video card drivers and reboot. If everything comes up, then you are all set.
• My system:
  • Athlon XP 1700+
  • Iwill XP333r Rev 2.1 1220 Bios/ 2.34 HPT drivers
  • 256M Corsair DDR at 266Mhz
  • 2x 160G Western Digital SE HArd Disks
  • Windows XP Service Pack 1

If this page helped you out, email me and let me know.