Only turns on when physically closed?

[Mightymouse]

So I'm having an odd problem. I left my computer on and open for a while, maybe an hour or so, and when I came back it worked for a few seconds but then started acting like it was frozen, except it kept showing whenever I had new messages. I tried to force turn it off, but had to hold the button for about a minute before it worked. I tried to turn it back on, but there was no response so I closed it and left it alone. Now it's gotten weird, though, because it's started to randomly turn on on it's own while closed. If I open it all the way it turns off and still doesn't respond. I opened it just a crack and it seemed to work fine, I could even watch a video. But when I tried to restart it like that, it turned off and wouldn't turn back on again and now it just randomly lights up turns on and turns off again intermittently while closed. Does anyone have any ideas what I can do or might have done..? This seems super weird