NETWORKING WIN7 WITH XP LOSING INTERNET WHEN NETWORK OPENED

I have no problem networking the two operating systems and sharing folders and printers (use work not home on win7). BUT, the minute I open network and/or network sharing on the windows 7 computer I lose my internetconnection on both computers and have to go through a shut down of the w7 computer and unplug the cable modem and the router and restart everything. (The modem displays an internet connection.) Time Warner Aries Modem
Belkin G router

You can't get to shared folders without going through network. If you do you have to restart everything to get back internet connection.