|Can you exlpain a little better what you mean by "Windows wont work"? Does it boot at all? Does it get past post? Is Windows looping? Can you see any text before you get to the black screen?|
My guess so far is that you could have damaged the Hard Drive by bumping into the computer to hard. It might be as simple as repairng your OS, or as difficult as buying a new hard drive. But please give us more detail on your problem.