With two protocols, it shouldn't be that bad....is the W2K box up all the time? (Are you seeing many browser elections?) Are you trying to browse right after you bring up the W2K box?
Do the event logs show anything interesting? (Browser elections, etc..)
What DNS server is the W2K box set to look for? and is it on your subnet?
I know, lots of questions, no answers. Browsing can be a real PITA to figure out, because it's mostly automated by MS, so it's hard to tweak.
--Woodie