Constant game crashes

I dunno why but the game will run normally for about ten minutes then itll freeze. Sometimes it runs fine for ages and sometimes itll lock up within 30 seconds. The games it tends to affect are Pirates of the Caribbean, Railroad Tycoon 3 and Medieval: Total war.

I meet all the sys spec requirements for both and its not an overheating problem (I aimed the biggest fan I could find into it and it didnt help).

 

what are your computer specifications?

 

Patch up your games, Video card, sound card, and direct x.