Losing HD space, crashing, running hot.
My 2009 MacBook Pro keeps shutting down on me. I'll be working and it just goes black & restarts "because it encountered a problem." I'm running 10.8.3. I noticed recently that it has recently been processing slowly & I keep losing hard drive space as I work. It runs very hot, too - within 2 minutes of powering it up. To try to fix this I have recently replaced & upgraded my memory to 8GB. It hasn't improved anything. Just an hour ago, it crashed & attempted to restart, then crashed again before it was up. It did this about 5 times consecutively. Please help.
MacBook Pro, OS X Mountain Lion (10.8.3)