Help! Fail to connect a windows XP laptop via a wireless connect to Dlink router!

My laptop is hp pavilion ze4100, and I use Dell TrueMobile 1150 PC
card as the
wirelss card adaptor. I installed the SBC Yahoo! DSL, use a
speedstream 5100
DSL router, and a Dlink DI-514 broadband wireless router. My laptop
runs
windows XP home edition.

I try to connect the laptop to the internet through the wireless
router. The wireless adaptor can find the availble wireless network
with excellent
signal strength (11Mbps), but I just can not access the intenet
through it.

Notice:
1) When I connect the laptop and the router via a eathernet cable,
everything
works fine.
2) I use another laptop which runs windows2k, everything works fine
(wired or
wireless). That computer uses a D-link wireless adpator.

I guess:
1) It might be the xp's problem.
2) or it is the TrueMobile card adaptor's problem


Any one can give me any hint?

Thanks a lot!!!