No internet connection/wireless network

My sons computer has win98 se and has worked just fine connecting to the
internet thru'
a linksys wireless adaptor. Today I can not get his computer contected to
the internet. The
adaptor has excellent signal, I can see his computer on the network from my
laptop (running Vista) but we
get nothing for the internet.
My son said he installed some webtv thing that was on his computer to see
what is was and
it installed some kind of hardware driver stuff. He is not sure what. He
said he uninstalled the webtv
thing. I have no idea what he did but this may be what is confusing his
computer for internet connection.
Can someone please give me some ideas on what I can check for in the way of
settings and such. Thanks.