Frazzled PSU or MB?
 

I've been stripping down my old PC to salvage parts after it kept on having variable numbers of BSOD.
The problems got worse and worse until last month when I scrapped the PC and built a new one.

When I took off the 20 pin PSU to MB plug, I spotted that the bottom three socket pins were scorched as were the pins on the MB (MSI KT6). These pins are on orange cables but I have no idea what part of the MB they feed.
The PSU was a Thermaltake Purepower 480W. The PSU still starts up with no odd noises.
The PC was based around an overclocked XP2500 and OCd 9800 graphics card which also co-incidently gave up the ghost 3 months ago.

Is there a likely suspect for causing the problem?
I'd ideally like to keep either one of the components for an emergency PC.
Nick