Can you delete it outside of NAV? Open up the containing folder and delete it, if you cant delete it you may be able to rename it then reboot and delete it.
Also the NTFS permissions on the file may be set to SYSTEM only in which case you can take ownership the remove it, we can cross that bridge if/when we come to it however.
If you cant remove it i will create a reg file for you that you import to the registry, reboot and it will remove it at boot time.