Sorry if this finally shows up three times sooner or later but it looks like
Octanews is not
forwarding my replies today for some reason... so I'm bouncing this over to
news.eternal-september.org's host.
As someone already mentioned, give a Windows Restore a try if you can locate
a restore point prior to your sound problems starting. If that fixes things
good, if not then I would next try a Live Linux CD (no actual install onto
your PC's hard drive). They run directly from the CD and your computer's
RAM memory.
I would download and burn a Live Linux CD and give that a try. If you get
sound using one of them then you know that the problem is with the Windows
OS or drivers and not your hardware. With that info others should be able
to point you to possible fixes.
You can find many of the Live Linux ISO files at this link so you can burn
your own disk.
http://www.livecdlist.com/ Be sure to pick one of them that has Desktop
listed as a "Purpose" rather than just OS Installation. Puppy Linux or
PCLinuxOS are good examples of disks to give a try.