Getting IRQ error at boot up / BSOD

Hi gang, developed what I think is some type of hardware problem at boot up.

I'm getting the infamous "irql_not_less_or_equal" BSOD error at start up. Here's the error code at the BSOD screen (can anyone decipher what it means?):

*** STOP: 0x0000000A (0x0000014C, 0x00000002, 0x00000001, 0x804F4022)


Background:

Prior to this issue, my PC (an old rig P4 2.xGhz, 768MB RAM, Win XP, etc) was starting to "hang up" every so often and freeze (maybe 2 weeks ago?). I would push the restart button and it would run fine again. Eventually the "freeze/hang ups" would become more frequent until a few days ago when I was getting no video image at all during boot up.

I figured the video card, due to its old age, was responsible for the freezing and had died (it was an old ATI AIW 8500DV card, AGP interface).

So I replaced it with a new AGP vid card to get by and the PC would begin to boot up but then it ran into the above BSOD error message as soon as the Windows XP screen loads up.

I used the F8 key w/ "no auto reboot" selected to read the BSOD message (or it would automatically begin to restart). If I don't use F8, the PC will begin an infinite boot/restart process - doesn't matter if I select safe mode, etc.

I tried swapping in the old ATI video card and got the same BSOD error message so I ruled out that the ATI card went bad (doh!). LOL I've removed all other non-essential hardware devices (CDROM/DVD drives, sound card, etc) as well, to no avail.

Have also tried removing one of the two memory sticks (256MB and 512MB) and swapped them around to see if a memory stick went bad.

BIOS settings look OK and hardware monitoring is showing a processor temp of around 98F (which is normal for this box).

So I'm literally left with the processor, motherboard (Asus P4PE1), the 2 sticks of memory, power supply (Antec 480w), and the lone 80GB IDE hard drive. I've made no recent software changes either.


Here's a quick video upload to show what the box is doing at boot up without using the F8 key btw:

http://www.youtube.com/watch?v=GUgRnYPG0fg


What should I do next to continue the troubleshooting process? Thanks for your help in advance!

 

^ Thanks for the link on deciphering that fatal error code.

Did not run the system with no video card, thus I did not mess with the AGP/video settings in the BIOS when I attempted to swap in the new video card. I couldn't proceed far enough in the operating system to get an opportunity to load in the new drivers for the new video card.

I should clarify that I can't get the operating to load up while using safe mode. It will begin to load XP (as soon as I select the "mode" or if it timeouts and begins to boot) and then quickly flash the BSOD and then reboot on it's own (in the infinite loop).

Same also occurs if I select the option for "boot in last known working condition."

If I hit the F8 key, and choose the "don't auto restart upon fatal error" (or similar) option, the system will dead end at the BSOD upon attempting to load up the operating system.

Hope that makes sense. I paraphrased some of the above options/choices from the operating system...thx!