Reluctant Router

I have a D-Link DI-604 router that is giving me no end of trouble. The first one I had worked for a couple of weeks and then just quit connecting to the modem. I send it back and the vendor replaced it.
This time, I connected to it fine the first time to set my connection and username/password. It then refused to work and decided it would give me the admin screen when it was good and ready. Prolly about 4 minutes to completely refresh.

Anyone have any ideas? Oh, yeah--two computers connected to it. One Win98SE and the other XP Pro.

Art