Specs are as following

Quad core 2.5 ghz Q9300
4GB ram
ati radeon HD 3870 X2

Basically all my games from the Fallout trilogy on Steam hardlock my computer and I need a restart, the problem here is it's not as soon as I start playing.

I can play the game fine for maybe 20 minutes then for no reason it's just gonne freeze and hardlock my computer, not too long ago In Fallout 1 I killed the raider camp beside shady sands and then the inevitable, my game froze and hardlocked my computer.

This should be fixed now. Delete all local files and reinstall.

I tried and nope, I crashed after entering vault 15 and killing a mole rat and had to restart again after 20ish minutes of gameplay.