I had a computer once that would make a ghost noise 'WWOOOOOOOOOOOOOOOO' when you tried to start it up. I took it down to the computer store (this was before IRC, thus before I was awesome with computers) and it worked fine there.

When I got back home, it was ghost time again.

I thought about it logically for a while, and realized that the only change was the bumpy ride down, so I conducted an experiment. I picked the tower up and shook it vigorously.

It booted.

"orlllllllllly"

Thinking back, it was probably a loose hdd connection or something, but hey, shaking it helped.