If you travel often with your laptop then there must have been times when you've had to leave it alone momentarily. It's always a risk though but you can have some peace of mind with Laptop Alarm. Laptop Alarm does exactly what it's name suggests - sets off a high pitched alarm if someone attempts to take your laptop.
Not only that, but it blocks the laptop functioning correctly via triggering passwords and controls a series of parameters that can identify whether your laptop is in other people's hands or not. If somebody moves the mouse, it disconnects the USB connection USB and can even cut off the electricity supply if it's plugged in. In addition to all this, a loud shrill alarm goes off lasting several seconds until your attention has been alerted.
In order to deactivate the alarm and reactivate the laptop's functions, you need to enter the password in the main window of Laptop Alarm. This is not a 100% secure solution against theft and it would be terribly embarrassing if it went off by accident but it definitely provides some peace of mind.