Call of duty 4

Hey...
Got call of duty today and when trying to change the resolution i click yes to apply the resulution i selected and then the game crashes saying...

DirectX error:
"DirectX encounterd an unrecoverable error check the readme for possible solutions"

anyone had this problem before..if so please help me to resolve this!

also when trying to start the game up again it said this

It appears that Call of Duty 4: Modern Warfare did not quit properly the last time it ran.
Do you want to run the game in safe mode?

This is recommended for most people.
It will change your system settings but not your controls."


thanks
coookies