DialUp Connect Screen Appears on StartUp

I have two stand alone Win98SE PCs that intermitently display the dial-up connection screen to logon and connect to the internet after Windows has started. It may somehow be related to Norton AntiVirus 2003 Pro which will also bring up the connect screen sometimes when starting the Configure Norton AntiVirus Applet. I have the latest Win98SE updates, no virus/spy infections and have configured each PC for running any program or O/S updates manually, no automatic anything! Any Ideas?