I'm using a Gateway laptop using Windows Vista Home Premium 32-bit. I thank everyone for their previous responses but they simply did not work for me (probably because I didn't have a full understanding of each step). I reached certain points in the instructions where I couldn't locate the files being referenced (i.e., $winnt$.inf and mmdriver.inf), etc., so I couldn't follow the steps through to resolution.
After hours of trying to resolve an annoying issue with not being able to listen to my VOIP messages from work, I was able to
finally listen to my voicemails with one simple solution. I visited
Free file hosting by Savefile.com and downloaded an .exe application which installed the necessary drivers for me. I then restarted my laptop and, voila, the voicemails played just fine on Windows Media Player.
(Geloe777 on
where to get DSP True Speech Audio CODEC? provided this solution on 27 Jul 2007. I hope it works for you!!!)