About a week ago I rescued the lonely hull of a custom PC from the landfill at a flea market for $2. From that I got... - 3GHz Pentium D dual-core CPU with stock cooler - Asus P5B-VM SE - Antec Minuet 300 & 300W Antec slim PSU - 80mm Antec Tri-Cool fan - 512MB Corsair DDR2 400MHz Then I... - Added a spare 640GB 7200.12 - Replaced the memory with 2GB DDR2 400 from a Dell I have - Added a SATA optical disc drive Spoiler The drive had a pre-existing Win7 install from the Dell it was in, so I hooked it up into the rig and ran that install. Everything worked alright, but it was randomly shutting off. I thought it was from mismatched drivers, so I wiped the drive and installed Win7 so it would match up with the new hardware. Now that it has a clean install with the proper drivers, it is still shutting off. Sometimes it can be used for an hour with no problem, other times it shuts off 3 times or more before it can even fully boot up. Each time it's like someone is yanking the power cable out of it. I wiggled the computer around while it was running, with no result. That shows that it's most likely not a loose cable. One thing that tends to set it off is installing Windows updates. Almost every time I click "install updates" and it starts doing it's thing, it dies. So there are a lot of different things I could try. I'm thinking of moving the guts to my little mATX test bench with another PSU to see if that case is causing a short or that slim PSU is messing up. What else could I do to get this thing running right? I'd like to get it up for sale soon. Thanks.