XP pro and dial up disconnecting

I've got a new dell computer since my other one got fried by a lightening strike.

On my old computer, the dial up would stay connected if I was away from the computer for awhile.

This one, however, disconnects if I so much as go get a glass of iced tea and use the ladies room.

I've tried going into my internet connection properties, options, and changed the idle time before disconnecting to 4 hrs, 8 hrs, 24 hrs, and never. It still keeps disconnecting when I leave it for more than 10 minutes. I've rebooted in between all the changes too.

Is there something else I should do? I can't remember how I got the other computer to stay connected, but it had XP home instead of XP pro.

Any ideas?