Alright I'll post what what the problem is, plus what I did to try to resolve the issue and my observations. Thank you for taking your time to try to help me!! Last night the sound went totally out of Civ5. No sound what so ever. Other programs work fine, but my steam installed Civ 5 game no sound.... What steps I took. 1.)Rebooted the computer-no sound. Shut down and powered it back up-no sound 2.) I deleted Civ5 from my steam account and re-installed it-no sound 3.) Re-installed the sound driver on the motherboard and my G510 Logitech keyboard. One thing I did notice, when I logged in under DX 9 the sound was there. When finally before writing this I tried the DX10/11 version no luck. Any advice would help thanks again for any input.