I've got a Pentium 4 2800 MhZ, but I believe it runs fine on a 1 GhZ too. Only problem is the graphics card =/ Oh, and Phoenix is right.. Your computer is dead ='( you need a new motherboard for a new card as well I believe. Windows only change crashing in games, not lagging =/ in some cases XP has crashed games, but it doesnt crash ESF, any windows is good as long as you can play Half Life on it.