lookup problems

I'm using ADSL through a Zoom modem and USR 8054 router. The problem is
that my laptop (Dell Inspiron 5150) is having a really hard time
looking up names for some reason. IE, Mozilla, and Firefox all say
"looking up ..." for 20
seconds or so and then give up. HOWEVER, when I type "nslookup ..." I
get an immediate response and can use that ip address to browse the
site. Strange huh? It does this both when I'm connected wirelessly and
through an ethernet cable. The computer upstairs (also connected
through the same router) is perfectly happy though. Not a single
problem. The only way my laptop will work normally is if I unplug it
from the router and re-plug it in (not "repair" the connection or
disable and reenable it). Even then, it only works normally for a few
minutes and then it's back to lookup problems. This has got to be a
problem with my computer right? By the way, I was going to see if a
firmware update for the 8054 router would work, but www.usr.com refuses
my connection. Anybody else?