I'm having a similar problem. I rebooted my computer a couple days ago, and got the IRQL_NOT_LESS_OR EQUAL error. The STOP notice had the following register addresses: STOP: 0x0000000A (0x00000166, 0x00000002, 0x00000000, 0x804F5BC0) I have no freaking idea what this means. I don't think it's my video card, because I swapped out the one that was in there with the one I started with (I upgraded a four or so months ago), and I still got that problem. If I try and boot in safe mode (any version of safe mode), it hangs on agp440.sys, and nothing. When I tried to do a repair off of the Windows XP install CD, and then told it to use the "last successful configuration", instead of getting a blue screen or the start screen, it just goes to black after the XP load screen (the little scrolling green boxes under the XP logo). Not black with some icons. Just black. The GUI could be there for all I know, but I doubt it. Considering that the monitor is working up to that point, it's not a monitor failure. I have no idea what to do, and I can only hope that my harddrive is recoverable at this point, as I have files on there that I haven't backed up anywhere else. (Most everything I can reinstall, but some things I just don't have anywhere else.) Any ideas?

Please use the search bar at the top of the page for this.It has been answered so many times in here that all anyone else will do is refer you to that same page. rc

To resolve this issue, disable the Agp440.sys service: IMPORTANT: You must know the administrator password to complete the following procedure. If you do not know the administrator password, contact your system administrator. After you complete this procedure, any video adapter driver you have installed will be disabled, and Windows XP will use default VGA drivers. Insert the Windows XP installation CD-ROM, and then restart your computer. When the computer starts, press F12. Start your computer from CD-ROM, and make sure that you select the drive that contains the Windows XP installation CD-ROM. In the Microsoft Windows Recovery Console, select R for repair, and then press ENTER. Select the installation number for the problem installation. Type the password for the administrator account of that installation, and then press ENTER. You receive a drive:WINDOWS> prompt, where drive is the drive on which Windows XP is installed. Type listsvc, and then press ENTER. Make sure that the Agp440 service is listed, and that the startup type is set to "Boot". Press ESC. Type disable agp440, and then press ENTER. You receive a message that the registry setting for this service was found, and that its current startup state is "service_disabled". Type exit, and then press ENTER. If you are prompted to start in Safe mode or Normal mode, start in Normal mode. Log on to your computer.