So decide what best fits Your needs and budget. The only wrong answer to the initial question is not doing anything . A small but effective security tool that traps your mouse inside a small window. The only way to free it is by entering your password. You can have Mouse Trap run in hidden mode, and have it load when Windows starts up.
Encryption is accomplished by simply dragging and dropping files.
To decrypt a file, simply just double-click on it and enter the passkey.