Xp blue screen trouble

[kirby]

I have a rather perplexing problem,

I run windows xp professional sp1

and on reboot 1 day i got a blue screen error
IRQL_NOT_LESS_OR_EQUAL
i tried safe mode and debug mode but the system rebooted beforei could run any kind of diagnostic or recovery

apparently it was a hardware problem although i didnt change any hardware although i did change the direction of my heatsink, i didnt move or change any other hardware.

In desperation i tried formating but when i load the windows installer after copying the install files to my hardrive the sytem hets another blue screen error this time with no cause but the technical information:
serial.sys - address f8c415b4 base of 8c40000, datestamp 3b7de097

i need a faste reply so ill post this in the windows section as
:well sorry for any trouble: