I am having similar problems to that 69 dude. I had a 250W PSU running a p4 1.4 3 HDD's and a cd-rom drive. It ran fine for weeks after I put the extra two harddrives. I figured that because the power plug is there to be used it should work fine. When I turned the power on yesterday there was a strange crackling noise coming from the PSU and the led's on the motherboard were flickering lightly. It didn't sound good, so today I bought a 300W PSU, hooked everything up and turned the power on but nothing happened. The PSU was making a strange high pitch whining sound. I tried different power leads and power points but nothing. I am wondering whether this has fried my motherboard. Or if its the motherboard that is stuffed up and not the PSU. One thing I think I might have done wrong was connect the power plug to my floppy drive upside down. I am no electrician and need to know what's going on with my system. Is there anyone who can tell me if its the PSU or more likely a problem with my config. Cheers.