Why does it shut off shortly after turning on?

When turning on the tv, it stays on for a short period of time, anywhere from 30 seconds to 5 mins. Just before it shuts down, it makes a buzzing/whizzing sound, then the screen shuts off, but you can still hear the audio for about 10 seconds, then it turns off completely. Once it turns off, the lights on the power button flash (Lamp, Timer & Stand By/Temp). I just replaced the bulb on it today, thinking that may have been it, but it is still doing the same thing. Any ideas?

EDIT: I decided to start looking over the boards to see if any thing looked fried, didn't see much on the boards, but when I got to the color wheel, I noticed the small piece of glass on the casing of the color wheel assembly was cracked. Not sure if that would cause the problem that I have or not, but im sure it can't be good. I spun the color wheel by hand, and it does sound like it may have something rubbing against each other while its spins. The plug to the magnetic board looks like it may have over heated as well.