Realtek no audio. WIndows 7 Toshiba Laptop

I am hoping that someone here will be able to help me. While I was installing a Logitech software, I suddenly realized my audio had a red cross. Since then I was not able to hear anything. When I click the icon says reinstall the Realtek driver, I tried to do that by downloading from cnn downloads the driver but no luck, still says I can't install it. Please somebody help me. I do not know what I did wrong. Can somebody help me to fix this?

With Thanks

Kim

I have tried many places including the Toshiba site. The only message I get is : No audio Output device is installed, can somebody help me to get my audio back.

Thanks.

I disabled it and enabled it. The message is "Windows successfully enabled i, however this device is still not working properly"
I do not know what I did wrong. the audio was fine. I do not know how to get it back.

I tried to do that unfortunately I didn't create a restore point. I restarted and chose Last Know Config and didn't help either. ;(

Thank you so much. I did what you said. I unistalled from device manager still I saw the red cross. When I uninstalled Logitech and then reboot I saw the volume icon without the red cross. I didn't install from Toshiba agiam because I already have downloaded it previously and from the toshiba site.

Thank you thank you so much!!