That software is only required to get the modem up and running, once it's up you can remove the software and put the modem back on your LAN like normal.
I ran the stupid ATT DSL modem into a router which fed quite a few Linux and Windows machines for several years. Every once in a while the modem would freak out and I would have to plug a Windows laptop directly into it, with the ATT software loaded, to reset the modem and get it working again. Once it was working again I would plug it back into the router and everything would be back up and running like normal.
I'm not sure where ALL of the software they install lives, but you should be able to get rid of the vast majority of it through Add/Remove programs on your Windows box. Just be aware that the next time the modem freaks out, you'll need to reload the software. It might be worth just using a junk laptop for the job (if you have one).
Last edited by suicidaleggroll; 09-27-2012 at 07:05 PM.