Maybe it wasn't a corrupt file at all !
It could have been the Filesystem that had errors and needed a format.
Examples:
If someone formats the Nuvi to NTFS or in a MAC then the Nuvi won't work until it is formatted back to FAT32 using RMPREPUSB (not in your case)
Also if the Drive has lost clusters or another filesystem error it can cause the Nuvi not to work until the filesystem error is properly corrected.
A nearly flat battery can cause filesystem errors if the Nuvi dies due to lack of power while it is booting up. We've had such a case in the forum on a 3790 with a bad battery.
Please Charge your Nuvi at least once a month if it is not in use.

I think that you could safely put back all the pre-loaded original files such as help etc etc. (check date stamp to find preloaded files)
Try to avoid putting back files that get updated regularly such as voices text etc etc.