Cleaned out MacBook, Now won't start

So I replaced my keyboard on my white macbook late 2008 and thought in doing so id clean up the fan and board (which definitely needed it). Took out the motherboard and cleaned it with a toothbrush, then replaced everything but now it won't start properly.

The hard drive spins and the fan seems to try spinning when you turn it on and off (but only briefly). The display stays blank and the white led doesn't light either. Pulled it apart and checked all the connections but no luck :/

why would the hard drive run if the led doesn't as they're on the same connector?

Any suggestions?

Thanks