A little background on the situation before I start onto it. The computer I am having a problem with is a Dell Optiplex GX150, with 512MB RAM and a 1 GHz proccessor. A few months ago, while I was in my PC support class in high school, which I am now graduated from, I talked to my teacher about a problem I had been having in which the computer consistently rebooted before the OS loaded for anywhere from ten to thirty minutes, then loaded up completely and had no problems. He told me that it was likely a problem with the OS, that something was unable to start up and it was reparable. Since then, I've tried my hardest to find a forum online to fix said problem, but all to no avail. I unplugged the computer and put it away, taking the Hard Drive out of it. I got a new computer with a new hard drive, an eighty GB one, and decided to try it out, to see if It would load without the old hard drive, substituting the new drive, cause this computer isn't near as good as my old was and cannot support the video card that the computer had. When I first tried the old computer, It made some beeping noises, which in PC Support I learned could be a result of RAM problems, so I switched out the RAM with my newer(Though pretty much junk) computer. When I started up the computer again, there was no noises other than the normal noises when starting a PC, but then it would do nothing else, the computer screen would stay black and it seemed like it was in Standby mode, but it never came out of it, no matter how long I waited. I fiddled around with it a bit, but all to no avail and now it is back to the way it was after I changed the RAM, less the RAM of course, which is in the computer I am using now to post this. I would like to know if anyone could help me with this problem. I'll list the system again below. Dell Optiplex GX150 512 MB RAM 1.0 Ghz Proccessor If any more information is needed, I will supply upon request.