If Scannow did not fix your issue...
Did you just start having the problem..or has it been present since you installed?
If you just downloaded something (MS Update or anything like that) have you tried to use System Restore?
I found a lengthy link about PnP Software Enumerator at: http://www.annoyances.org/exec/forum/winxp/t1066427444 [Read carefully, as I think some of the posters are referencing Win98 or WinME, as opposed to your OS.]
Although you may have found the problem being the drivers.. you dont state where you are getting the updated driver from. Here is a link to the latest audio driver from Biostar: http://www.biostar:usa.com/mbdownloads.asp?model=M7NCG%20400
Also, boot up in safe mode, and make sure you only have 1 appearance of drivers loading up under the Device Manager.
If all that is fruitless, you can always email Biostar, as it is quite possible they have heard of this issue before.