I built a computer for my niece a while ago, and for awhile it was running smooth as silk. Now it seems to have a nervous breakdown every couple of months. I suspect her stupid friends are screwing with it, but she says no.

I haven't been over to check it out in person yet, but she says that while the memory/ hardware check seems normal, she gets nothing but a blank screen, and no Windows logo.

She tried booting to the Windows disk, but the machine just hangs at "Setup is inspecting your computer's hardware configuration".

Are there any suggestions as to how to troubleshoot this problem?