MacBook Pro turns off when tilting backwards or forwards, also overheats

I have not seen this issue here before and I have had this since I have owned this machine. Yeah, I know, I'm an idiot for not doing it during warranty time but that's an entriely different discussion! When I pick my MacBook Pro 15" Unibody (Mid 2010 model). I sit with it in my lap, as do most of us I assume. The machine runs fine on normal applications but when do anything audio od video related, the temp rises quickly. I have a fan controller installed and I use that, and it seems to keep it at normal levels. The biggest issue I am having is that when I move the computer off my lap anda tilt it backwards or forwards, it shuts off! What a pain in the arse! It is quite frustrating. I've learned to work with it but I'm at the point now where I want to get this fixed or at least know what the problem is. I t happens whether plugged in or not. I was going to attempt re-seating the battery and maybe the logic board connections. Has anyone out there run into this issue? I may just have to take it in to the Apple folks but if I can take care of it myself I would rather do that. The computer still runs great and I plan to keep it for a while.
Thanks in advance.


do an SMC reset
it sounds like it would fix your issue.
if not:
Take it into apple.
The macbook pro's have a sudden motion sensor that will lock your hdd if it is being moved to prevent any damages.