My laptop (Win 7, Toshiba Satellite - C850D-11Q) is having issues with booting up.
If I try to boot normally the screen appears to turn on for 1-2 seconds, then off again and loops like this continually. If I try to boot from DVD, its the same. The laptop is in a loop, as opposed to the screen not working, as I can enter the BIOS after it has restarted as described.
I can enter startup disk, but unfortunately if I try to boot by USB I remain in the bootup loop.
Due to the above I can run any diagnostic checks using DVD/USB and there does not appear to be any built in checks built into the BIOS.
I've removed the HDD, checked using Disk Utility on OSX, and it appears to be fine.
I can boot into BIOS as normal. Which would suggest that the screen isn't the issue.
Any advice as to what the issue may be would be greatly appreciated.
UPDATE: Followed PIMP_JUICE_IT suggestions, checked for damage, cleaned out dust, removed HDD/RAM,
As Big Chris suggested I tried removing and replacing the thermal paste, cleaned fan/radiator, but unfortunately the problem remained.