GSFinder is an existing file explorer originally developed by Y. Nagamidori (who also made GSPlayer).
Abandonned by its original author, it has been totally remade by Mitsuru Toda, from a HPS version, then PPC, and for the first time as an 'international version' in English. As for functionality, interface and ease of use, it is in my opinion, it is the best freeware (even better than certain commercial apps...): support for all machines from the old MIPS up to WM2003SE with VGA supprt, ZIP management, network management, file searching, powerful context menus (copy to, move to...), Windows standards compliant, tree view, favourite documents and folders, etc.
Unpack the file to your desktop using winrar
You should now have 1 folder
(Step 1) Remove your SD Card from your navigo or V2,V3 and insert card (insert new card here if you wish(see notes below)) into a card reader on your pc (most printers and PCs have a port) explore windows to find your SD card.
(Step 2) Once found - locate (folder) "mobilenavigator"(not the one on your desktop, the one on your SD Card) and rename "old software".
(Step 3) Now - drag (folder) "mobilenavigator" from desktop into the window. IF YOU GET AN ERROR(or file is already found) at this point make sure you have completed the (step 2) above or read (notes) below. P.S. It may take some time to copy files.
(Step 5) Remove SD card and Replace into navigo, navigo V2 or V3, hit your navigation button, done.
(notes) If you unsure at any time use a new blank SD card and do (step 1) and (step 3) not (step 2) , just insert your orginal card if you get problems.
You can reload your old software by locating the (folder) "old software" and clicking the icon "mobilenavigator".