Sound stopped working

Of everything that you have done but try what should have been the first steps Run a Virus Scan on the system and then some Mal Ware Scans in [b]Safe Mode.[/b]

If you do not have any currently loaded Mal Ware Scanners you can try these which work quite well

Ad Aware SE

http://tinyurl.com/qoppr

Spy Bot S&D

http://tinyurl.com/yrwy2

You can download directly from the above links and after these are installed you'll need to update both programs and maybe reboot as well. But when you have everything updated you can boot into [b]Safe Mode[/b] and here I do mean Safe Mode nothing else by pressing the [b]F8[/b] key between the BIOS Screen and the first Windows Splash Screen and then run the Mal Ware Scans after Windows has loaded and remove any infections.

I always start off with Ad Aware as it's the easier of the 2 to work with and allow it to clean up whatever it finds then run the scan again to make sure that it's actually removed the offending files and that there was nothing hiding under these. I keep running this till it comes up as clean and then run Spy Bot.

Now this is where you have to be careful as Spy Bot will pickup a few False Positives things like Windows Defender or whatever it's called now will be picked up as well as quite a few Internet Banking Programs so you'll need to remove the tick from beside these programs or they will be disabled before you run the repair option.

When you have run the repair rerun the scan just to make sure that you are only shown the files that you want or the system comes up as clean.

I don't know if this will do any good but it may be worth a try it's from the M$ Knowledge Base with instructions for how to recover from a corrupt Registery

http://tinyurl.com/4y24g

Col