Good luck with your upgrade Bird! I had a similar problem as you describe (dial up, connects, but, won't talk to anything) and I beat on it for a while (and I know where to beat these things!). I finally did a reinstall.... So, hopefully your reinstall will clear things up for you.
I haven't played much with XP yet, but, I've always had better luck with wiping the hard disk clean and starting from scratch. Of course this mean you must have a way of backing up your data (including things like your favorites list if that is important to you) and then you must reinstall all your add-on software. If the XP CD you received is an "upgrade", someone else with XP experience may want to speak up to tell you if you need an existing OS on the hard disk to perform the "upgrade"...
I'm sure others will pipe up with more "advice"... /w3tcompact/icons/smile.gif
Like I said before, good luck!