A few days ago I came into my room and noticed my laptop sounded like it was running hard. I opened it up and it was frozen. I had to manually shut it off and restart. I didn't think too much of that but now the past two nights I've left it running. When I wake up, I hear the computer running hard again but when I open it, the monitor is completely blanked out. It is not the power settings. It is not in standby or hibernate. The only thing that will restore the image on the monitor that I can tell is to again manually shut down and restart. It seems to be abnormally hot when I find it in these situations. But I'm not sure what's coming first. Is it overheating causing something to fail? Or is something failing causing it to overheat? Any help would be greatly appreciated.
Here is my computer.
Sony Vaio PCG-K27
3.06 GhZ Pentium 4
512mb ram
Thanks in advance.

check for viruses. i know that with laptops the monitors supposed to go blank after you shut it, but its supposed to come back on when you open it. if you have a virus of any kind it could be causing your processor to work in overtime (which is what it sounds like to me when you say it sounds like its running real hard) if youre not using it and your fans are goin real heavy that means somethings running in the background and that can cause it to freeze when you open it back up to use it. also if you have pets you may want to take the case of the laptop apart and vaccuum off the fans, hair and dust buildup can cause it to overheat or get real hot real fast too and if thats the case then the rising temp is whats making it freeze.
thats about all i can think of, i hope i helped