XP won't boot, only reboots

[bygeek]

XP home system won't boot in regular or safe mode. Stripped to only video card. All fans working normally. Cleaned cpu fan & heat sync.
Replaced power supply.
Swapped out ram.
Swapped out video card.

Boots to splash screen, the reboots with no error or BSOD.

Attemped repair install or recovery console from cd, but it reboots even off the cd before it gets to the options. The hard drive was totally formatted and everything reinstalled from scratch a week ago.

Am I looking at a fried mobo or processor?

Any ideas/suggestions most appreciated asap.

Thanks.

 

[linney]

Will it let you enter the Bios? Perhaps resetting that to Default might do something?

Otherwise it sounds expensive.

Check the hardware forum.

 

[bygeek]

Already reset bios to defaults, thanks.

 

[shakru]

I had the EXACT same problem when installing XP home on a hard drive that already had NT on it. The problem was with the HD, not the mobo or CPU. Had to order a whole new hard drive and install XP on that, then with both drives hooked up I could get into my old files and transfer them to the new drive. I'd recommend trying to reformat/reinstall windows first but if all else fails, this worked for me.

 

[bygeek]

Tried another hd, system rebooted in the middle of windows install. Now getting BSOD with MACHINE_CHECK_EXCEPTION errors.

On a whim, I disabled the L2 cache in the bios, and it boots up ok and hasn't crashed yet. Obviously this is not an answer since it runs so slow, but does it confirm my theory that the processor is bad?

 

[linney]

http://www.certification-forum.com/aplus/machine_check_exception__101330.html

http://www.memtest86.com/

http://oca.microsoft.com/en/windiag.asp

Memtest86 - A Stand-alone Memory Diagnostic
Memtest86 is thorough, stand alone memory test for x86 architecture computers. BIOS based memory tests are only a quick check and often miss many of the failures that are detected by Memtest86.

Once more check your RAM (I realize it is new), but is also cheaper.

Have you posted on the Hardware forum, they will be better qualified to help you decide whether it is time for a new motherboard?

 

[bygeek]

Linney, thanks for the tips. I ran the microsoft memory diagnostic and it failed in the first pass (MATS+) at 004de000-1fff8000. No error, just froze up the program. Swapped out memory chip and ran again - failed at exactly the same spot. Disabled L2 cache in bios and ran again - no errors. Does this confirm the L2 cache on the processor has failed? I've never heard of this happening, but I suppose anything is possible. I'm going to post this in the hardware forum also.

 

[linney]

Does this confirm the L2 cache on the processor has failed?"

Anyone else know the answer to this, because I don't?