ISP "times out" after several minutes

[poorjim]

I am using XP Home Edition w/SP1. My ISP is DSL Extreme. I use FireFox as a browser. After I have established contact with dslextreme.com the connection holds for several minutes then shows "No Server Found", "Timed out." If I restart the PC, the same process repeats. When I hook up the modem for DSL Extreme to my other PC using XP Professional (no SP's) the connection to the ISP works flawlessly. The connections to the different PC's are manual and direct (no routers, switches, networks, etc.) Are there any settings either in IE or FireFox that control how long the ISP is connected? - poorjim