XP Sound Hardware Test Wizard problem

To check the operation of a microphone I started the Sound Hardware Test Wizard in the Voice tab of Sound and Audio Devices Properties.

The first time I ran it, it stopped shortly after starting it and gave an error. I forget just what it said but it mentioned dpvsetup.exe.
A Google search led me to this page http://www.smartcomputing.com/techsupport/...=&ErrorID=22221 and I carried out the registry changes it advised.

On running the Wizard again it stopped and gave this message "An error occurred during DirectPlay Voice setup. The error code is 0x80004005"

A Google for this coughed up dozens of leads and they seem to deal with totally different causes of the same error. I am therefore reluctant to try any of the advice.

Can anyone here help me please?