An attempt to run a program that's locked down will result in a dialoge box launching asking for the password.

Failure to provide the correct password prevents the program from fully launching.

EXE Locker is most useful in situations where you want to stop people from getting to certain files but don't want to deal with hassle of constantly encrypting and decrypting those files every time you want to use them.

For example, password protecting your copy of the Real Player negates the need to lock down every single Real audio/video clip on your computer that you want protected.

EXE Locker is great for keeping people out of your personal stuff (locking Quicken so your kids can't snoop through your bank accounts) and for preventing unauthorized use of programs they weren't meant to touch.