Problem w/ WEP after installing SP2

I downloaded and installed SP2 for XP Pro last night. Since then, I haven't
been able to get my wireless connection running. I'm running a d-link 802.11b
router with a d-link 802.11g wireless card on an Athlon 1.7 GHz cpu, 512 Mb
RAM, and I boot from a 20 gig hard drive (data is stored on a second volume).
XP Pro was freshly installed about two months ago, from the upgrade CD only
(I did have to put the old Win 98 CD into the drive to continue the install).
All drivers are up-to-date.

If I disable WEP I connect with no difficulty, but once I enable WEP, the
Wireless wizard doesn't seem to like my key. The key is valid on two other
CPU's, neither of which has SP2 installed and might not if I can't get this
straightened out.

Does anyone have any thoughts?