Detection of a microphone is not necessary. I'd go to the audio control panel and make sure it's not set to "mute". I believe most are by default to prevent feedback through the speakers.
Everysince I set up my home wireless network my WinXP Professional and WinXP notebook no longer detect any microphone attached to the machines.
I have tried and tried again to find a solution to this problem. Many times I have gone to the Control Panel > Sound and Audio Devices > Voice > Test Hardware and tried to run the wizard to set up the mic, but have failed.
Looking forward to hearing a solution