Based on what I have on my PC:
1/ Start-up: Nasnavi.exe (this is NasNavigator) and Nassche.exe (this is for automated tasks)
2/ Services: nassvc.exe (power management service)
3/ Check your firewall config and make sure all traffic from/to your NAS are added to "allow" list
I would suggest to completely remove your current NASNavi program, then clean all the registry by using CCleaner (google it). Once it is done, restart your PC and install a fresh (and latest) version of NASNavi.
Hope it helps