Try this free program and see if it does what you need.
Easy File Locker
Easy File Locker is FREEWARE.
Easy File Locker is a light-weight and easy-to-use file lock software product for Windows. It can protect your private files and folders. With its great protection, users will not be able to open, read, modify, delete, move, copy the locked files/folders, or even not be able to see it. The hidden files/folders will be totally invisible to all users and to any program.
Easy File Locker is designed for protecting files/folders on your local computer. it doesn't change the protected files and folders, it will not slow down the system speeds and it will never have the chance to destroy your data.
Keep curious eyes away from your private files
Lock files, Lock folders:
The locked files/folders are protected from accessing, users can not open, read, modify, move, delete, copy, rename the protected files/folders. Files and sub-folders in a locked folder are also protected.
Hide files, Hide folders:
You can hide your private files and folders, to make them completely invisible to users and programs.
Password protected GUI and uninstaller:
Once you set a password, no one can launch the application or uninstall the software without the correct password.