They’ll be lost.
If you want or need them, extrat them from Chest to a floppy or USB Drive, for instance.
Take care if any of them is infected !!!
Right click the file and choose Extract action.
You don’t need to extract the files on ‘system’ folder, because the ones there are for backup purposes.
Wait avast scanning…
But, after all, it’s a pity that you want to keep NAV… you won’t receive this kind of support from Symantec :-*