When you reinstalled Windows did you run Windows Update repeatedly until no more updates were found? Did you source your drivers from anywhere other than Windows Update? Have you checked in Device Manager that there are no devices with a yellow triangle and black exclamation mark next to them?
In your System log there are hardware error messages like this one...
Rich (BB code):
Log Name: System
Event ID: 18
User Name: NT AUTHORITY\LOCAL SERVICE
A fatal hardware error has occurred.
Reported by component: Processor Core
Error Source: Machine Check Exception
Error Type: Bus/Interconnect Error
Processor APIC ID: 0
The details view of this entry contains further information.
A Machine Check Exception is an unexpected hardware event, detected by the CPU. Therse are often genuine hardware problems, but it could also be because a device driver is missing/wrong/corrupt.