Hello there, I've got a 2011 MacBook Pro 17" and I recently opened it to clean it of any dust. I removed the two fans, cleaned the dust, reinstalled, removed the optical drive, cleaned, reinstalled, removed RAM and cleaned under there, reinstalled. Put the screws back on for the bottom casing and... no power, no lights, won't even charge(no lights on cable either). Nothing, nada, zip. I've triple checked all my cables, and unplugged the battery to drain the motherboard of power. I've checked to make sure the power is grounded to the aluminum case, it is. I never had an issue before. I also tried resetting the SMC, nothing. Any ideas? I'm at a loss.
Also, I feel like I should not that my battery was at like 85% battery.
Go to www.ifixit.com and look up a repair guide for that model MacBook. I would choose one for removing the logic board since it will show you all the connections. Then make sure you have all of them back where they are supposed to be. I would pay special attention to the power connection and the keyboard connection.