Go to
Uniden USB Cable and download the Vista driver for the USB-1 cable that you have.
Check the Hardware Manager and see what com port the new driver is assigned. I think FreeScan will allow you to search for radios connected to the computer if you don't know what Com Port is used.
You might also want to check that you have DotNet installed. FreeScan should do this for you by sending you to the MicroSoft web page for the latest version (3.5.x I think....). You can see what version you have by going to the "Add-Remove Software" control panel.
Enjoy!