I have Windows 7 Ultimate 64bit and the Buffalo WLI-UC-GN working flawlessly!
I have found this solution works for many wireless devices over all Windows Vista and 7 OS.
I am not sure weather this contributed but I downlded and installed first (to no immediate avail...)
- Find and turn on Network Discovery on your pc.
DONE!
*Network discovery being the main solution. I have installed many USB wireless broadand modems in the last 12 months and have discovered this through trial and error of modems that would not install correctly.
Hope this helps. : )