I got the exact same wireless adapter and had this exact same problem...
This happens because you installed the complete software package (which includes the driver), and now it is conflicting with Windows XP built in wireless support. The two software packages (linksys' and windows') are fighting with each other over who should be in control. Go to ADD/REMOVE programs and uninstall the linksys software and reboot your computer. When you get the new hardware wizard popup, click cancel.
Now before you did what is stated above, you should have downloaded the attached zip file in this post, which includes the drivers needed for the WUSB54Gv4. You also should have already extracted these to a folder where you will remember its location.
Now go to START-->RUN and type devmgmt.msc
to bring up the DEVICE MANAGER. In the new window that appears, you should notice an item with a yellow question mark next to it. Right-click this item and choose UPDATE DRIVER. The update driver window will now appear. Select No, not this time.
on the first screen and click NEXT. On the next screen, select Install from a list or specific location. (Advanced)
and click NEXT. On the next screen check the box for Include this location in the search
and then click the BROWSE button and locate the folder you extracted the files to from the attached zip file and click OK. Click NEXT. The wizard will now search for, find and install the driver. It may pop up a window about the driver not being tested by Microsoft for compatibility, but just click CONTINUE INSTALLATION. Once the installation is finished, reboot your computer and your problem should be gone and your WUSB54Gv4 will work fine.
*EDIT* -- The zip file containing the drivers for the WUSB54G can be found HERE.
Edited by Fenor, 01 January 2007 - 03:42 PM.