To avoid problem with the windows virtual stores you should not install to the default location of program files but instead install to somewhere like c:\Airnav.
Also if you installled from the disc initially and then installed the 3.13 or 4.03 upgrades you will have 2 different versions on the computers.
When installing the Navdata you require to guide it to the correct data folder. With the both versions installed if you dont direct the Navdata to the correct location there is every likelyhood that it will go to the wrong data folder and then when you turn on your Radarbox software the update will not be read the correct one
Options
1. Delete all instances of Windows completely and then download and install the 4.03 from the Airnav website, installing to c:\Airnav. Thereafter downloadand install the update and direct it to the correct location. Dont point to the data folder only go as far as c:\Airnav\Radarbox
2. Use Windows search to locate all instances of Navdata.db3. and when found replace the old one with the new one. Therafter when installing the update direct it to the correct data folder only going as far as Airnav\Radarbox.
3. Leave both versions as they are and download and install the update directing it to the correct data folder again only going as far a Airnav\Radarbox.
If you need any help give a shout out and we will assist you to get there.
Alan