Lock Desktop…If you've been looking for a way to lock your desktop but leave your programs and data open, look no further. Lock Desktop does just that. Installed on the Dock, one click will provide you the security your looking for.
If you have multiple users on your computer, you can login as any of those user accounts after locking your computer. That leaves the first account's programs running in the background and does not show them as running in the login screen.