I have a free trial version of NetGenius. The program in running, and its service is running and listed in services.msc. However there are no computers, applications or processes shown in its main window. The list is totally empty. And when I click the "Connect to..." button, the drop-down list of computers there is also empty.
How can I get the computer I want to monitor to display in that list?
It sounds like your connection was removed, perhaps accidentally. You can re-add it and re-connect.
For that, click the Connect to... button, and type localhost in the name field (and the password if you had set it). Then click Ok to connect to your computer. Please make sure the word localhost is entered precisely like this, without spaces or other alterations.