Hmm, this's a problem with buying online.. never quite sure..
Try seeing if you can borrow a PSU from a comp shop, test it in your comp, just plug it into the mobo, no need to do the rest. If the system starts up fine and if you have the internal pc speaker and it beeps? your psu was shot. Thank god i have a bud who works at a comp shop, so I just need to ask him stuff. Heck, I've gotten a free Thermaltake volcano12 HSF cause some n00b tried to force it in with pliers and bent the vents, I just unbent, and bam, free $70 (well, if it were new and undamaged) HSF, not bad eh?
But now? I would've rather gotten a gigabyte 3d rocket cooler.. my comp would be soo much better...