My old desktop PC is a Medion MT7 Pentium D 2.80GHz, 2g Ram, running vista. I think this maybe a PSU problem, but before I go out & buy a replacement I thought I'd check in with the experts. The PSU is a FSP300-60GTM It started not to boot when I had my 2 external HD's plugged in, so I made sure to disconnect them prior to powering it up and it worked fine. However it started acting up again, and eventually I worked out the DVD drive also needed to be unplugged for it to boot this time. This worked fine for while however now it randomly just turns off after so long (plugging in my usb-powered external HD will trigger it 50% of the time) + will only boot 100% of the time if I disconnect the c drive in addition to EVERTHING else When I say it doesn't boot, I mean I press the power button, it powers up for 3 seconds, and then turns straight off with clicking sound from the PSU. No beeps or any warnings. It seems to me like the PSU is steadly 'losing' its wattage, as I have to keep disconnecting more & more things to get it to boot, and when I plug them in again once it does boot, it's only a matter of time before it turns off again.