Games not opening?

[Wavobabies]

Hello, I recently bought Clear Sky, and two days ago, when I tried to open the game, the thing just... didn't open. The same thing happened when i tried to open CoD4, the whole thing popped up with the banner-ish thing, with the marine on it, and when it would've opened, a message came up saying
"Direct X encountered an unrecoverable error

Check the readme for possible solutions"

I'm really stuck on what to do here, and ANY help at all would be very useful to me. for any info you have.

Oh, and only post constructive comments, if possible.

[Trooper110]

Try reinstalling directx imo

[Ghost_Rain]

yer that will work