I have a friend's laptop at home with a bit of a strange issue. If i boot the laptop it works great for about five minuets then the LCD starts flickering a bit and then it goes black. If i use the VGA socket and connect it to my TV it works great no problems what so ever.
I thought it might be a bad driver but it does the same even if i leave it to idle in the BIOS. He had vista on which i replaced with Windows 7 just because vista sucks. I know it's not a driver or OS problem cause it does the same in the BIOS.
I did open it (as far as i could) and checked the connections but it all seems fine.
Check the power saving options in Windows and see if the issue might be caused by an attempt to go to low power energy saving mode. Put the setting at High Performance and see if that changes behavior.
It that doesn't work it sounds as if the laptop screen's cold cathode fluorescent lighting (CCFL) tube is going bad as it heats up.