I am not sure if this is the right section for this question, if not I apologize.

I am fixing a computer for a friend and have a problem that I cannot find a solution for. This is a 6 year old custom built computer which runs GREAT now but has a weird issue still remaining. When running scans or immunization with SpyBot search and destroy or deep scans with SUPERAntiSpyware the computer reboots itself. SpyBot gets through about 1400 files on scanning before reboot, and not at all on immunization, but it will update just fine. SuperAntispyware will get through about 75% of a deep scan before it reboots. I cannot find any other programs on the MACHINE which cause this to happen.

I have run other programs such as AVG, Malwarebytes etc, which complete their scans with no problems but report no infections found.

I have tried un-installing and reinstalling these programs but the problem remains.

Inside the computer it is clean as a whistle with no dust or dirt build up remaining.

The device manager SHOWS no problems with any drivers.

The machine does have four fans inside. One on the back of the case itself, one on the graphics card, one on the CPU and one on a heat sink sitting on the motherboard itself with AGP 8X written on it. This last fan does not appear to be working but the others are.

Everest program shows the internal temps to be :
Motherboard 38 °C (100 °F)
CPU 63 °C (145 °F)

Since these appear to be within normal operating range for the type of motherboard and CPU, I don't think it is a thermal issue.... But I could be wrong.

When I set the system to not auto-reboot after system failure, running the two programs results in a BSOD which does NOT indicate a specific DRIVER or other issue as a cause. It gives a generic stop message beginning with 0X0000008E which apparently relates to a hardware issue. However there has been no new hardware or software installed prior to the issue appearing last week and everything else is working very well.

Does anyone have any ideas about what could be causing this? THANK you.

Paul