Wireless Performance Paradox on Thinkpad T42p

Hi All:

I would like to run something by the people here. I own a IBM Thinkpad T42p.
I have installed a wireless router in my parents home for when I visit
(Netgear WGT624 802.11g). When I use my T42p to go to a back room of the
house, I get unstable signal strength (anywhere from 7% to 100% - but
usually somewhere in between). The adapter speed is usually between only 2-6
Mbps at this location. When I try to access the internet (via browser), I
get the typical response for no internet access. (When I test for internet
access with the Acess Connections tool, it likewise says no internet
access.) OK, so it's out of range - or so I think. What's strange is that I
can use XP remote desktop to log on easily to my desktop computer directly
wired to the router with good performance. Then, of course, I can access the
internet through my remote desktop terminal display on my T42p at this
remote location.

Can someone help me with this technically? Why can I access my desktop
computer on the LAN at this distance (via router) and yet not access the
internet? It seems that if I can route internally to another computer and
connect via Remote Desktop terminal services that I should just as well be
able to connect externally to the Internet. Is there a setting or something
on the Thinkpad I'm not aware of?

By the way, as soon as I leave the room and get a bit closer to the router
so the signal strength and adapter speed jump up a bit, I can access the
internet. And, of course, the wireless internet performance of the T42p when
in the same room as the router is excellent.

Thanks in advance for your help.

PS. I have all the latest wireless drivers from Lenovo.