I think i deleted my sound

[gcoats23]

Ok im a complete noob to this. I was trying to get my ATI card to not flash a black screen when i play games in fullscteen mode. I tried everything until i decided to turn off the ati propriatary driver and try and install another one. well half way through the guide, i saw that the flashing during fulscreen mode was because of compiz. So i renabled my ati drivers and disabled Visual - now my game works great, but i did edit my Xorg.conf and i think i deleted my sound because now my icon in the top of the screen shows its muted and when i click on it i get this message "No volume control GStreamer plugins and/or devices found." Also when i click on preferances i get nothing. I will continue to llok throught the forums. thanks if you can help me.
here is my system adn Xorg - btw i dont know how or where the device manager is in Ubuntu

Dell inspiron 9100 2.8 ghz dualcore 512 mb ram
ati 9700
Broadcom Wireless ---havent got it to work yet
ac'97 sound- i guess-

I just got this message after a restart --also i went into services and enabled sound --
The volume control did not find any elements and/or devices to control. This means either that you don't have the right GStreamer plugins installed, or that you don't have a sound card configured.

You can remove the volume control from the panel by right-clicking the speaker icon on the panel and selecting "Remove From Panel" from the menu.

so anyone got ideas