Hi,
Ok I got it now,actually the PC is running fine(touch wood),no additions to  the memory and runs well on Win 7 64 bit,
Yes my sons got a biiger power supply for his games.
Had some blue scree issues wind xp 32 bit a while ago but the Pc had not been reformatted for 2 years and it gets alot of work(on average 15 hours a day) but formatted 3 months ago and changed the OS and up to date no nasty things have happened.

Thanks for your help everone,Im now a couple of steps closer to understanding my PC.

p