Laptop fan makes roar when moving, what should i do?

The fan on my gateway m675 laptop is making a truly loud noise. The fan noise is not loud cause my laptop is running hot, but a physical problem with the hanger-on. If you watch the fan you'll see no problems and whether you take it out of the place in the laptop it runs fine. It's when it's in there it makes a noise like the fan is rubbing against thing. Not sure what to do. Tried compressed air and nothing. I need relief!