Recently i think i have been having troubles with my PSU. Started off with the system randomly switching itself off but some leds styaed illuminated. Id have to unplug the cable from the mains wait 10 seconds and then plug it in again. In the last day or two it has begun to switch off (by switch off i mean sudden power cut not shut down) when the system does something other than basic web browsing, eg when i play a game i get 15 minutes beofre it dies. I think its the PSU just wanted your opinions. The current one is 500W, its just over a year old, so no warranty. Worked fine till recently, no hardware changes have been made. I think i will go get another 2moro just to be safe, could it be anything else.

maybe your CPU is overheating? If you have a system intensive game, your CPU will heat up quite a bit. Does the room have adequate ventilation and stays cool? Do you have enough fans and a decent heat sink in your machine? Maybe download free CPU temperature monitoring software. Some motherboard mfgs. offer a utility for monitoring system temps. I have an MSI board, and they make PC Alert for mine, which works pretty good.

I don't think it's a temp issue...a p4 will just throttle down and keep on going If you have another computer, you can use its psu and replace/test the problem system. If it's not the PSU, it might be a mobo problem. The PSU is the backbone of the system...you should buy a brand name psu (antec, enermax).