Hi Anne--
I'd also try checking these items I use when sound is gone:
Check Device Manager to see if your driver is installed correctly. DM is
not reliable up through Vista if you can believe Redmond MSFT did that (they
did) for driver health (maybe next OS--Blackcomb/Vienna or some other ski
slope or city), but it is useful to see if a driver is installed and your
sound card entry is there.
In your run box type devmgmt.msc and see if you have a Sound, Video and Game
Controller Entry and expand it and see if your card is there>rt. click
it>properties>driver>driver details tab and see if drivers are installed.
Touch base with this checklist:
I Can't Hear Sound from My Vista PC:
http://windowshelp.microsoft.com/Windows/en-US/Help/1e87a3e8-c0e8-49af-980f-9eb6686f42d21033.mspx
and this one:
http://windowshelp.microsoft.com/Windows/en-US/Help/f76f244d-56db-4b68-b560-37eb4000253a1033.mspx
My personal ck. list:
1) Check connections from PC to your speakers and any other sound related
peripheral.
2) Ck Control Panel>Playback Tab>Rt. click Speakers and hit items on
context menu including Speaker Configuration and Test them; Click the
Properties button (lower rt. corner)>check the levels tab and make sure
nothing is preventing sound there particular the "Master" lever at the top.
Also on the Advanced tab check that the appropriate pull down menu item is
selected.
3) Get newest driver appropriate to your sound card by visiting the Sound
Card's website.
Some of these principles apply to Vista:
Resources for Troubleshooting Sound Problems in Windows XP
http://support.microsoft.com/kb/307918/en-us
Good luck,
CH