1. Choose Start, Control Panel and double click Add hardware, then click Next.
  2. Click "Yes, I have already connected the hardware" and click Next.
  3. Choose Add a new hardware device at the bottom of the list and click Next.
  4. Select "Install the hardware that I manually select from a list (Advanced)", and click Next.
  5. Select "Sound, video and game controllers" from "Common hardware types" list and click Next.
  6. Select "(Standard system devices)" from "Manufacturer" and click "Have Disk..".
  7. Click "Browse" in the "Install From Disk" dialog box and open the folder C:\Windows\System32 (or C:\Winnt\system32)
  8. Find mmdriver.inf file, select it and click Open then click OK in the "Install From Disk" dialog box.
  9. Now you should finally see a list of audio codecs. Among the items, you should find Microsoft ADPCM Audio Codec and IMA ADPCM Audio Codec. You need to install them one by one so select either of these and click Next. This should reinstall the codec and the Windows 2003/XP/2000 CD may be required.