In the last few months, about half the time when I boot up my computer the sound will not work except for Windows-related noises (shutdown noise etc.).
Also, If I'm booting up as the admin, I'll often get an error message that I assumed to be related the sound error, but may not be. I've attached a screenshot of the error message. When I click view technical information about the error report, I get this:
Does it always work immediately after booting up the computer? If yes, then the cause is likely caused by some program you are running (could be a web browser, etc.). Testing might be a pain, but you can try the sound after each program you run to get a clue as to what might be causing it.
I saw a couple of things. Under Applications tab:
Error - Application Error. Faulting module unknown. Category (100) Event ID: 1000
Under System tab:
Listed several times, there was an Error for DCOM. Event ID: 10016.
"The machine-default permission settings do not grant Local Activation permission for the COM Server application with CLSID
to the user NT AUTHORITY\LOCAL SERVICE SID (S-1-5-19). This security permission can be modified using the Component Services administrative tool."
You receive an error message after a Windows XP-based computer runs an automatic update, and you may be unable to run any programs after you close the "svchost.exe - Application Error" error message dialog box http://support.microsoft.com/kb/927385