Avid Pro Audio Community - Unsupported Device

I'm new to this, so bear with me. I bought my Protools LE system + MBox 3 mos. ago and have yet to use it. I originally installed everything, played around with it a bit, then let it go. Now I'm back and it seems like the system is not letting me start up again. When I try and open Protools I'm told "Digidesign hardware is in use by another application (-1133)" and the Disigidesign Coreaudio Manager tells me I have an "Unsupported Device." Nothing has changed since it was first installed and I can't seem to find the error in any documents. Something tells me this is going to be a really easy fix that's just escaping me now. Any help for this novice Protooler would be appreciated. Thx.