So I'm having some computer problems recently and I havn't the slightest clue as to what could be causing it. I really need an anons help.

So recently my computer has been freezing up on me. It usually does it about 5-10 minute after its been on but it only does it when I'm doing something on it, for example if I'm playing a game it does it almost after 5 minutes. The screen will freeze and my speakers will make this annoying buzzing or clicking sound repeatedly. I cant move my mouse cursor and I cant CTRL ALT DEL. I have to manually shut it off very time. Its only recently started doing this.

So to fix it I just did a complete system restore, reinstalled windows 7 and deleted the windows.old file. However it is still doing it. The thing is it only does it when I'm doing something on it. If I leave it alone over night it wont freeze but when I go to load a steam game or surf the internet for too long it locks up.

So yeah I checked all my drivers and their all up to date it says. Does anyone have any ideas as to what could be causing this?

Video card: ATI Radeon HD 5800
Processor: Intel Core i7 CPU @ 2.80 GHz
Motherboard: ACPI x64-based PC