Ok it sounds like you have played with computers before. The other thing you could try is to get another bit of memory from somewhere else…Also you can disconnect everything like the cd drives, remove add on cards, etc, then restart it. The only thing that should be in there is the mem and the hard drive connected to power. This is all you need to start the computer. If you have onboard video then plug the monitor in too...but if you have a graphics card that you have taken out and can't connect the monitor now, don't worry because you will be able to hear if the computer restarts again...If the computer doesn't restart, and is normal, start adding bits back into your computer. What are the specs of the computer?