Vaio VGN-FZ340e freezes without reason!

Hi,
I have a stock Sony Vaio VGN-FZ340E, and its freezing from nothing.

Sometimes I'm doing a lot of stuff on it, using WMP, chrome, corel Draw, and something else on, and everything goes ok, I close everything, the computer keeps running without any other program running toghether, than, it freezes! There is not a reason for it! Sometimes, I leave it turned on during the night to download something, update or do the virus scan, when I wake up next day, I see that it had frozen at 2am. I've already formated it using the vaio recovery disc, and nothing changes, it keeps freezing anytime, with so many different reasons for it.
I wish someone could help me with it!