|AlwaysWIlling asks a good question. Does this phenomenon occur all the time, no matter what the application, or only with certain applications?|
Firstly, I would download and install the newest driver, from Dell if you can. If not, here's a link to one:
Check to make sure there are no conflicts with the audio device: Go to Control Panel and Device manager. Click the "+" sign next to "Audio and game controllers" (Or something similar, it's been awhile since I've used XP) and see if there are any yellow triangles with exclamation points. If so, try and resolve the conflicts.
Another thing to check would be the Mic properties in the Volume control properties. Open the Volume Control panel and select Options then Properties. Make sure you select Recording and then make sure that Microphone is ticked. Press OK and adjust the volume of the microphone and ensure that it isn't muted.
As a last resort (for now), you can try this: http://h20000.www2.hp.com/bizsuppor...
If none of this works, let me know. We may have to edit the driver file for your sound device.