Actually lots of games have a minimum requirement above 1.3Ghz but with a decent graphics card, they should still run fine.
Find out how to enable the Frames Per Second counter in your games. Then tell us what the FPS is. If the FPS is high enough (>20) then we'll know it's unlikely that your computer is too slow to run the game, and it's some other problem.
Have you tried using PS/2 mouse and keyboard? Latest patches for the game? Also try using a "simple" keyboard rather than one with complex buttons etc, which might be causing some kind of interference for some reason.
But the FPS number is important, so please try to find it.