lilbrett :
My friend got a new gaming pc and he gave me his old one. The only parts it was missing was the hard drive and ram. The computer I had before was an Asus. It was a normal desktop pc and not custom built. I put the hard drive and ram into the new pc and the pc boots, however nothing appears on the monitor and there is 3 long beeps that keep continuing. Is this because I have stock ram in an aftermarket motherboard?
As GreenToxon wrote, this sounds like a problem with your ram. You'll have to figure out if the ram you have is compatible with the motherboard. If not, you'll need to get some that is. If it IS compatible with the motherboard then try clearing the CMOS and reboot. If it still doesn't boot at all after clearing the CMOS and you're positive the memory is compatible then it might be the power supply, either that it is bad or that it can't supply the power required to boot. Honestly though, I'd be really surprised if that was the case since you mentioned that the only parts you put in are a hard drive and ram.
If the computer DOES boot after clearing the CMOS but still errors out to a blue screen you may want to try running a system repair by booting from a Windows cd. Where I work we swap out hard drives between different models of dell computers every once in a while and if the models are too far apart they'll boot to blue screen and the above method is how we usually fix them. You'll end up with a very basic installation of Windows and you may need to go out and get drivers for the chipset, ethernet, audio, etc components on the motherboard, but it should at least boot into Windows at that point.
If the computer does NOT boot after clearing the CMOS and making sure that the memory is compatible you'll likely have to do a completely fresh install of Windows. For that I would recommend using a second hard drive so that you can copy over your data and files from the hard drive that currently has Windows installed on it. Unless there isn't anything on that first drive that you're worried about losing, of course. If you couldn't care less and have all the installation discs for the software that you want then go ahead and use the hard drive you have.