There seome problem with my notebook computer

I set up win7 system on my notebookcomputer,but afer I

finishied it ,I found it can't recognized the outboard

microphone,just recognized the one it had brought by

itself.I want to use it,then I downloand and set up the

voicedriver,but it still did't work,I think I shoud set

up some content in the system,but ...Who know that?

Thanks