Good guesses.
I thought the Mobo was fried, maybe had an intermittent fault (lots of problems with the BIOS not saving changes, changing the BIOS battery didn't help, which I didn't chronicle in an already long post) so went out and bought some new kit. Had to wait a day for a delivery of memory so put the 'fried' mobo in an old case I have and it worked fine right off the bat on a 230W rated PSU...
The PSU in the stack I received was rated at 350W, I doubt it was pushing out more than 180. It just so happened that the power consumption was right on the edge, it would work with a stripped system but seemingly even putting some strain on the graphics card or plugging a CD rom in would tip the balance, hence the crashes...
The system was built in 2003, at which time it was top notch. Naturally the geezer (not my mate) put top of the line components into the cheapest case he could find...
Sometimes the computing Gods just have your number.
