Can't get DSP True Speech Codec 22 to work on XP

I have a WAV file created by a call recording package. When I try to open it in Window Media Player 11 it says “Windows Media Player cannot play the file (or cannot play either the audio or video portion of the file) because the DSP Group True Speech (22) codec is not installed on your computer." I have downloaded the codec and installed it, the files are present in c:\windows\system32 and the system reports that this codec is installed, but still I can’t play the file. Anyone have any ideas??

Thanks in advance
Dara

Sorry for the late reply.

Check out my post here http://www.moviecodec.com/topics/37173p1.html
I put manual installation instructions for XP. You state you installed a codec and Windows reports the codec as installed (assuming you’re talking about the correct one: DSP Group TrueSpeech). If it didn’t work, I can only suggest the following: delete tssoft32.acm from your C:\Windows\System32 folder, then delete the associated registry key: Run the registry editor (start, run, regedit), navigate to the key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32 make sure Drivers32 is highlighted, look for msacm.trspch on the right pane, right click it and choose delete.
Then do everything I listed on my post on the other page http://www.moviecodec.com/topics/37173p1.html