Try the following:
Click on Start > Run > type devmgmt.msc
Expand System devices, and check that 'Plug and Play Software Device Enumerator' is present and is "working properly".
During the routine you may see "Driver is enabled but has not been started".
If it's not present, or not "working properly", or you get the above message, try the following:
'Plug and Play Software Device Enumerator' is missing or not "working properly".
This fix may work, although this should normally be taken care of by reinstalling the audio drivers:
1. Insert your Windows XP CD and find swenum.sys - either in DRIVER.CAB or SP2.CAB. Copy it to the proper location noted above. Also put it in C:\Windows\System32\drivers. If you don't find it or can't do it, just skip to step 4.
2. Do a search in your Windows folder for machine.inf. There may be more than one location, but note down which one you select.
Open it (double-click) and locate (near the top) the line "ExcludeFromSelect=*". Put a semi-colon followed by a space at the beginning of this line to disable it.
3. Look for this line near the top: "SWENUM.CoInstallers.CopyFiles = 11 ; %windir%\System32".
"%windir%\System32" indicates that the file swenum.sys should (normally) be located in the C:\Windows\System32 folder.
Close machine.inf, saving changes.
4. Go to Control Panel => Add New Hardware. Follow the wizard and manually select to Add System Device. Click on 'Have disk'. Navigate to machine.inf. You will have to do a search in your Windows folder. In the list of Standard Devices on the left, select "Plug and Play Software Enumerator" on the right. Finish the installation.
Restart the computer.
Hope it helps.