My computer worked just fine until I switched my hard drive to a different computer and switched it back to my original. It goes to the black screen and says that windows failed to start, and that a software or hardware change could have caused the problem. It gave me the option to either run startup repair or run my computer normally. When I run startup repair, my computer just freezes on my desktop. It doesn't even load my background or my icons. When I run it normally, it just gets stuck on starting windows. What could I do to fix this? Using windows 7, by the way.