So I have this old PC my dad wants me to fix up. I have no idea on the specs, there is no model number or anything that tells me either. Anyways, about a week or 2 ago it was working...ok. I was just screwing around with it, replaced the old DVD drive in it with a SATA instead of an IDE, put a different HDD with the intent of hopefully getting Windows 7 on it, and 2 GB of RAM as well. All was fine and everything boot up back then (I have yet to put Windows 7 on it, that was my plan today until the problem started). Well, this was the PC I plugged that IDE HDD with a short into, which those who replied know it stopped the PC from booting. After unplugging that HDD from the PC I found it to boot fine again, and figured all was ok. Well, now it's doing that same thing with the error beep and after some research I found it could be a multitude of problems. I already checked the RAM, the RAM is good. I checked the CPU for bent pins and such and that's all good. I went and removed everything except for the CPU and RAM and attempted to boot it up and still nothing. So now I think it's a PSU issue, but I'm not 100% sure. I have spare PSUs around somewhere and will replace it tomorrow, however I just wanted your guy's opinion before I do so. Is it the PSU? Or is it something with the Motherboard?