Why is my computer not loading?

What version of windows are you using and do you have a disk for it? Some things to try before going overboard on running repair programs . First unplug the computer so it has no power then hold the power button down for a 60 second count . This will allow for a clean boot . Next if this brings no joy boot into safe mode(would tell you how if I knew which version of windows you are using) with command prompts then run an sfc scan this will repair most files and if not it will prompt you to run the repair disk . If it will boot in safe mode run a virus scan as many viruses emulate a system failure . Something else you may want to try is removing one stick of ram and running only one if no joy try the other one . Bad ram caan cause a blue screen error. Hope this helps