Cathy1, don't worry about the DX 9.0c. If you install a game that needs it, let the game install what it needs.
Read all the games I tested and played in the Windows 7 and Games thread stickied at the top of the Glitches forum. I never installed any DX version except when installing a game. Still haven't for that matter!
In my PC corner for the winter, gaming, knitting and reading.