Not really sure if this helps, but I go through these steps every time this happens to me.
Disable Antivirus and Firewall.
Run all the .exe files inside the FGunZ folder as admin.
Disable DEP for all the .exe files inside the FGunZ folder.
Right click computer > Properties > Advanced System Settings > Performance > Settings > Data Execution Prevention > Add the 3 .exe files there.
If this doesn't work, maybe someone else has another fix.
