I don't have Windows 7, but this works for 64 bit Vista:
1. Go to
http://www.usbuirt.com/getstart.htm and get the Windows Vista / Windows 7 Driver .zip file.
2. Save the .zip file somewhere you can find it. Your Desktop will work fine for now.
3. Right-click the .zip and choose Extract All...
4. Accept the default location and name by clicking the "Extract" button.
5. Plug in the USB-UIRT.
6. When Windows finally decides it can't find a driver on its own and asks you to put in a disk or browse to a folder containing the driver software, point it at the folder you just extracted from the .zip.
Windows should then find and install the USB-UIRT drivers.
Once it finishes, you may want to restart your computer just for general principals, but mine didn't require that and next time I started BVC... viola! Working IR!