Assuming you have an LCD, there is no lamp.
First, try the ol' unplug power, wait 60 seconds, plug back in trick. If that doesn't work, try turning it on and hitting menu. If you can see the image by holding a flashlight at an angle to the screen, you have a bad backlight - call Toshiba for a concession. If you don't see an image, there is a good chance you need a mainboard.