In the computers and backup screen, you can select the computer to see the list of available backups. That screen will also show the operating system of the client PC. If it hasn't backed up, you can check a couple of things.
1. Make sure the connector is installed and working. If you can see notifications and open the dashboard, then it should be good.
2. If you had used Discovery.exe to re-establish the connector's link on the PC, then you may need to configure the backup. You can do this from the console or by right-clicking on the connector icon on your PC and selecting "configure backup".
Hope this helps.