I have the opposite problem. The modem connects allright in Win98SE, but in Windows XP, it hangs and freezes XP up soon after I've logged on to the server.
But if I hang up the connection manually immediately after connecting and reconnect, it doesn't freeze my computer and I can browse and download without problems. What could be causing this? I have the latest drivers for the dialup modem (Motorola chipset) and SP2 installed.
It's a clean XP install on an empty hard drive, with McAfee's Anti-virus. I don't think it's an adware/spyware problem, since this problem has existed ever since the first connection. (I don't even know why disconnecting and connecting again works, except that it does.)