need some help

im putting together a better computer for my mom since i had most of the parts for it from my last computer before i upgraded so i know all the parts work, but i didn't have a psu, so i bought a cheap cooler master 350w that newegg had on sell, when i got it i hooked it up, fired up the computer, looked around in the bios, then restarted and started to installed windows, but i noticed one of the fans wasn't moving, so i shut down to see why it wasn't working, i fixed the fan and then tried to start the computer back up, but it wouldn't start, i played with it for hours but it wouldn't start, so i rma'ed the psu, i just got the new psu to day, i hooked it up and fired up the computer agine, it boots fine but i get a drive error, i forgot to plug the hard drive in, so i shut down, plug the hard drive in and restart, but it wont start, now i know these psu can't be this crappy that they die after one boot, so can anyone help me, what im i doing wrong another then using this psu?

Maybe there's a short somewere. Check to make sure all the connectors look correct. Like the pins are actually and everyone of them are functioning correctly. It's hard to explain but that might be one problem. Don't try to start your comp up until you've done this. This could take out alot of stuff PERMANTLY if you don't check.


PEACE