online sound problem

the problem is that when I'm online there is no sound, none at all.
my sound is fine off line,with the exception of the videos I downloaded from youtube (with real player sp) they have no sound either. my sound was fine until about two weeks ago, I let a friend use my laptop to check his credit card balance. he used IE8 and was on about 15-20 min. shortly after that my pc started acting up. the next morning I tried a system restore. but I kept getting error messages. so I downloaded spybot s and d and ran it. I had a virus.after some investigation I found out my friend had turned off my antivirus and malware.mad:I don't know why) after another system restore every thing seemed fine with the exception of no sound online, my updates wont download and install automatically and my uninstall doesn't. I've tried everything! checked the registry,device manager, ran microsoft fixit for sound and system, installed the vista ultimate codec pack, checked mixer setup, and tried to check audio setup in firefox, but there is no check box. (tools, options, Looked all over but nothing). I'm at my wits end. I don't want to restore to factory image, cause I would lose everything, and my backup disks have gone awol!
anybody know of a solution that isn't as extreme as starting over,or to expensive?
I'd really appreciate the help, Thanks

 

You system seems to be infected.

Please post in Malware and Virus Removal section.

 

ran malware and avira anti virus system is now clean, but still no sound online. trying to reinstall flash player, but my firefox says missing plugins (it cant identify) so Its slow going,any and all suggestions would be appreciated. thanks