You'll probably have to uninstall all the drivers, then do a registry scrub and remove all traces of the USR drivers as well. Finally, I'd also do these fixes.
For XP:
WINSOCK Fix XP:
http://www.spychecker.com/program/winsockxpfix.html
Reset TCP/IP Stack:
http://support.microsoft.com/default...&Product=winxp
For other Windows versions:
WINSOCK Fix WinALL:
http://www.cexx.org/lspfix.htm