Microphone's USB bandwidth.

I know what you're thinking. The 746382292728393rd person to ask this question.

Anyway, yes. My computer has recently been throwing up errors regarding me not having any spare USB bandwidth. I can deal with this, I know how to fix it, and so on. Well, not quite... the PC only throws up this message when trying to access a microphone... I don't have one plugged in. And the one I would plug in... has audio jack connectors? Last time I checked, that wasn't USB.

I know a common solution is to get a new hub, etc, etc. But why am I getting errors about peripherals that don't exist? Is there any way to tell my PC not to access a mic?

I'll include specs fro you all, just in case.

ASUS Nforce 500 M2N e-Sli mobo (seems to be problematic amongst many)
Asus/Nvidia GeForce 9600GT 512
Corsair xms2 Ram - 2x1Gb
EnLight Sniper 600W PSU
500Gb Seagate Barracuda HDD
AMD X2 5000+ CPU @ 2x 2.61 ghz

Thanks in advance.