To prevent this from happening again, we will add a confirmation message for the computer removal in the next NetGenius release.
To add the removed computer back to the list, simply click Connect to... button in NetGenius toolbar, then in the "Connect to computer" field type either
localhost for the current machine, or the computer's name (and password, if it was set) for a remote computer. Click Ok and your computer will reappear in the list.
It is important to understand that application limiting and blocking takes place in the System Service. Even when the applications are removed from the Management Console, they are still being managed by NetGenius Service according to the blocks and limits you set for them earlier.
The fact that NetGenius Service works separately from its Console means that all your blocked applications remained blocked, and your privacy and security weren't compromised. However, this also means that if at some point you wish to stop managing a computer with NetGenius, simply removing it from Console list won't be enough. You will need to either remove all the set limits and blocks, or uninstall NetGenius Service from that computer.