My laptop is a Toshiba Satellite L500 and the screen has started going off after a second or 2 of use. For the brief time that the screen is on everything is clear and displays perfectly. Restarting the laptop or even just closing the screen and opening it again displays the screen for a second.
The laptop is otherwise working fine and I'm able to use it connecting to a TV through HDMI
What are the likely causes of this behaviour?
UPDATE
The Toshiba Diagnostics Tools reports a PASS on all tests.