Wireless connection problem after upgrading to Windows XP SP2

I recently upgraded my desktop computer from Windows XP SP1 to SP2. Now I
can't establish a wireless connection. I am using a Linksys WRT54GX router.
The desktop computer connects with a WMP54GX pci adapter card. I had a solid
connection with SP1. If I rollback my installation of SP2, I can get
on-line. I'd like to keep my installation of SP2. I contacted Linksys but
all they suggested was deleting my preferred wireless network and recreating
it. I've looked all over the internet for possible solutions. It seems that
many people have experience similar problems with their wireless networks
after switching to SP2.

Here are the things I have tried:

1. deleting my preferred network and then creating it from scratch
2. manually configuring a static IP address
3. turning off the Wireless Zero Configuration service
4. switching from WEP to WPA encryption
5. using the linksys utility to configure my connection
6. using windows to configure my connection
7. uninstalling my pci card and then reinstalling it
8. using the repair option in the Wireless Networking tab

These things I know for sure: DHCP is enabled and the "Enable 802.1x
authentication" option is also unchecked.

If I do not use a static IP, I get a message that says "Acquiring network
address" but it never connects.

If I try using a static IP, I get a message saying that the connection is
made and connection strength is excellent but I cannot actually get on-line.

I do not know if Windows XP Hotfix Q815485 is on my computer. I will try
removing it if it is there and see if that helps.

Any suggestions any of you have would be greatly appreciated. I really
don't want to rollback my SP2 update.