how to change WEP password on SMC PCI card?

Some time ago, I set up a wireless network in my apartment, using an
Apple Airport base station. I connected to the network using an SMC
2602W EZ Connect PCI card in my Dell desktop (Windows 2000). I didn't
set up any sort of encryption.

The base station recently died, and my roommate bought a new Linksys
router so we could get online. He gave me a WEP password, which I was
able to plug into my Mac iBook just fine. Unfortunately, I cannot get
onto the network from my PC anymore. What's worse--and really
embarassing--is I can't even figure out where I would enter the WEP
password into the wireless configuration utility. The utility is
showing that it's getting a strong signal, but it can't get online.

Any suggestions would be very, very appreciated!

Thanks!