i had same problem,i am running win 7 ultimate 64-bit. my solution was to open window xp either on a old pc or maybe you can extract from a win install disk ;C:\winnt\system32\drivers\mrvw245.sys copy that file to a usb drive, take to win 7 pc and copy that file into c:\windows\system32\drivers. plug in wireless adapter and there you go. windows found the driver and i had no problems from there, the wusb300n is working flawlessly