Looping reboot on XP SP2 - multiple motherboards and multiple hard drives

[i am looking for xp help]

I have an xp sp2 computer (lets call it PC1 with hard drive HD1) that I
have been experiencing period stop errors (x0000001a) and looping
reboots (safe mode only goes as far as MUP.SYS) after several months of
error-free operation after an SP2 upgrade.

I took HD1 out of PC1 and replaced it with another hard drive with a
working installation of windows xp sp2 from another pc (lets call it
HD2 and the second pc PC2). I experience the same looping reboot with
HD2 when it is installed in PC1.

So this would imply that I have a motherboard/bios issue with PC1,
right (same error, two hard drives)?

But here is the puzzle. I took HD1 and deleted the partition, did a
full NTFS format and re-install of XP with SP2 on PC1. After
completing installation and getting ready to insert an Office XP CD, I
encountered the stop error and then the looping reboots began again. I
then installed HD1 in PC2 and I still get the looping reboots!!!

To summarize:
PC1 with HD1 : reboot after MUP.SYS
PC1 with HD2 : reboot after MUP.SYS
PC2 with HD1 : reboot after MUP.SYS
PC2 with HD2 : works normally.

My question: If the problem is with PC1, why would I have the same
problem with HD1 on PC2? If the problem is with HD1, why would I have
the same problem with HD2 on PC1?

Any help on this would be great. My next step is to reinstall XP on
HD1 using PC2 as the installation device.

Is there such a thing as a virus that can infect back and forth between
the BIOS and the hard drive? I have never had both hard drives
installed in the same machine simultaneously and both machines were
protected by up to date Avast antivirus.

Thanks in advance

 

[DL]

You cannot swap the hw for a winxp installation without running a repair
install of win