Gahhh! I didn't fix the laptop

I spoke too soon I finally got hold of some thermal paste and reassembled the laptop. Everything looked fine it powered up and had installed all the latest windows and software updates it had missed during it's illness. I closed the lid when I'd finished then when I opened the lid to use it again and it won't power up! Flashes the cap lock LED five times to indicate the same fault! Piece of s.....