Files not backing up with new computer

My laptop (windows 7) died and the replacement has Windows 8.1. When I connect My Passport via USB the external drive is recognized and my files are all there. However, the files are not being backed up as they were before. How do I get the backup working again? Thanks.

Did you install WD SmartWare on the new computer? Your WD Passport Wireless is holding your files, but WD SmartWare is the one storing your files into it.

Great - I asked another dumb question! Here’s another one: I don’t think I ever had an installation disk, did I? Can you please point me to the correct link to download WD Smartware? I’m not sure what I should look for. Thank you and thanks for your patience!