Computer frequently freezes up programs and sometimes restarts

[Simski]

A few days ago around christmas, my computer has started acting very odd.
It frequently freezes up while I'm browsing the internet and the windows say "is not responding". I can still open up some windows I have open in the background, some things remain functioning, but I can't open any new windows, and pressing ctrl + alt + del does nothing.
It does this randomly while on the internet, but it has also happened while I'm using skype...

It has also happened while playing the binding of isaac, tf2, and dark souls. With TF2 and DS, it has completely restarted the computer only to be stuck on login... and before doing so it briefly displayed lines on the screen and an odd "eeeeeeeee" noise. While playing Isaac... it shut down everything in the background, still allowing me to play the game for a few minutes, but then it restarts.

I've updated all my drivers, installed all windows updates, and done virus searches with 3 different programs... I've uninstalled several programs installed around the time of christmas... but generally, nothing has really worked and the problem persists

[djjkxbox360]

Check temps, something could be overheating. There's a program called HWmonitor that's best for checking temps

[Simski]

I've talked with my friend a bit. He suspected it was my harddrive, from having read some user complaints. We made a backup copy then installed a possibly risky patch, and it seems to have been working for a couple of hours now at least.