You can test your microphone using Sound Recorder.  Go to Start->Programs->Accessories->Entertainment->Sound Recorder.  With Sound Recorder, you can record from your microphone and playback your recording through your speakers.

You can also check to make sure that your microphone is selected as your recording device.  Go to Start->Programs->Accessories->Entertainment->Volume Control.  In the Volume Control, choose Options->Properties.  In the Properties window, choose the Recording option and click OK.  You will now be looking at the Recording Control, make sure that Microphone is selected and then close the Recording Control.

Often, Windows mixer settings can be adjusted to improve microphone problems.  In other cases, the is a problem with the microphone or soundcard.

You can test your microphone using Sound Recorder.  Go to Start->Programs->Accessories->Entertainment->Sound Recorder.  With Sound Recorder, you can record from your microphone and playback your recording through your speakers.

You can adjust the sample quality the Windows using when record from the microphone.  Go to Start->Settings->Control Panel->MultiMedia (sometimes Sounds and MultiMedia).  In the MultiMedia Properties window, choose the Audio tab.  On the Audio tab, click the Advanced button under Sound Recording. In the Advanced Audio Properties window, move the sample rate conversion quality slider to Best and click OK.  Click OK to close the MultiMedia properties window.

You can also adjust the microphone recording input level.  Go to Start->Programs->Accessories->Entertainment->Volume Control.  In the Volume Control, click Options and choose Properties.  In the Properties window, click the Recording radio button and make sure that all of the control are checked, then click OK.  Adjust the Microphone volume control to about 3/4 (our application uses automatic gain control, you do not want it much above 3/4).  Then click Options and choose Properties, this time choose Playback and click OK.  Now, click Options again and make sure that Advanced Controls is checked (if available).  If there is an Advanced button under the Microphone control, click Advanced.  In the Advanced controls for Microphone, if there is a gain settings, you will want to try your microphone with the gain setting on and off and see which sounds best.