Problem with wireless card in w2k

Hi, I have just installed win2000 professional. I have a wireless
card Conceptronic C54C. The thing is that I installed the drivers,
utility program, etc. and everything works fine (the card is
activated, etc). I have also correctly set ip address, dns, etc.
The problem is that the card only sends packets! I cannot
receive a single packet. What could that be?
Strangely, I installed winXP on that machine just to test if the
network card works ok (because I want to install win2k) and
in winXP it works perfectly!
I thought about a driver problem, upgraded the drivers to
the latest found in vendor's site. Same result.
I can only ping to localhost. Any other ip address doesn't work
(I get time out)

Any help, pointer, etc?
TIA!