do a system restore on me to before dx9 was installed.
install the latest dx9 compatable drivers for your graphics card ati click here nvidia click here or from the pc manufacturers website.
reinstall dx9 click here (this version just download and install like any other software)
even if your graphics card is only dx 8.1 compliant dx9 is still required for some of the latest games to run and will work ok with most cards.as ? ???K??M? says above make sure your drivers are up to date first.