try this (taken from another thread):
Go to device manager and select your audio device from the list and open it.
Click on the 'Driver' tab and select 'Update driver'.
Let the computer try to do it automatically first and if that doesn't work, choose to find the driver yourself by browsing to it.
Now, there should be a folder, probably on the C: drive where your drivers are extracted to when the driver package runs. Try to locate the Realtech folder and see if there is a sub-folder that contains 64-bit and 32-bit files.
This is where the relevant .inf files should be.
Browse to this folder, depending on whether your system is 32- or 64-bit, in the 'Update driver' screen and locate the .inf file.
Open it.
Does the driver install?