MacBook Pro Fan loud at startup, no display or sound

I just cleaned my mid-2009 Macbook Pro fan by opening the bottom and disassembling the fan (without disconnecting it). I used a lint-free cloth that I use to clean my glasses to wipe the dust off the blades of the fan and reassembled everything.

When I went to turn it on again, the fans just run really really loudly and there is no beginning chime or display.

Any ideas?

Thanks!

The best suggestion I can give you is to open up your MBP once more and check to see if everything is in place. Take special note of any ribbon cables or connectors that may have been accidentally disconnected or broken.

Use the instructions and views provided at iFixit: The free repair manual to double check.