I recently had trouble with a WG511 V2 on a Windows 98se system.

The card would work, but would not consistantly get an IP address from
2 different routers I tested it with. Would work some of the time I
booted up, but not others. And when it did work, it would work at
first. I'd wait 10 minutes or so and window would pop up saying "You
are now connected to the Internet". Again, same issues at two
completely different locations.

I know I re-installed the driver, spoke to Netgear's support, etc.
I think I even updated the driver at once point.

Tonight I installed a 2 yr old Belkin 54g PC card in the same laptop
(after uninstalling the Netgear card), and it works perfectly. So the
issue is with the card. To make matters worse, I also had problems at
that location with the Netgear router. I got the router going after
support had me click on the Mac Address area to update it, and it
worked the rest of the right. When the user tried again in a couple
days, no longer worked. I suspect the AC adapter could also have an
issue because this router worked fine for months.

My advice would be to return the card and try a different one.