Download this package if you’re looking for a WUSB54G V4 driver which works on Windows 7 64 bit
wusb54g -- v4
So this is what you do:
1.) In Device Manager, disable and then uninstall your adapter. Get into Device Manager by right clicking on “My Computer” and Click Device Manager in the left hand panel.
2.) Download and SAVE to your desktop the 64 bit version of the rt2500usb driver ( http://mystuff.tk/files/Linksys/bilal_dot_ca_linksys_v4_x64_driver.zip )
3.) Create a folder on your desktop and Unzip to your folder.
4.) Now back in Device Manager, click on the “scan for hardware changes” and when the window pops up to update software for your wireless adapter you will want the option to browse your computer for the software.
5.) Navigate to the folder you just created and extracted the files to on your desktop. Windows will install the drivers and you are set. (dont pay any attention to the name windows uses for your adapter)
6.) Connect to your network. 
7.) DELETE all the crap you just downloaded from your desktop.
Don’t worry about Windows calling the adapter a different name. Enjoy.
