clean registry of all NF files using "regedit" in command prompt

theres programs that can help you uninstalling,
i've used 'revo uninstaller' to remove stuff completely before in the past

To uninstall the game you need the original NF installer, downloadable from this website.

Uninstalling via Windows App list does not work.

But Genera is right (thanks for the hint):
1. Download the Installer from this site
2. Run it as you did when installing NF - it offers you to repair, modify and remove the game.
3. Choose "remove".  It will remove the game from your windows app list and remove most of the files and registry entries. It also seems to remove the game guard software.
4. There still remains some data files in the "FleetMission" game folder. Search and delete the folder manually.
5. Finally delete the installer program you just dowloaded manually.

However - software that does not uninstall correctly seems not very trustworthy.