Reading http://www.sevenforums.com/general-discussion/120882-locking-your-computer.html I see how to set Windows to not do that but your post sounds as if the laptop has died.
Did you try the generic reset? Noted in the CNET Laptop Troubleshooting Forum here's the short version.
Remove AC, battery, press and hold the power button for 60 seconds, release, slip in battery, apply AC and try again.
opened laptop n msg on screen "locking your computer", it's not doing anything, have no idea why it's doing this, shut down didn't work, removed battery, tried booting up f11, nothing....