you don't specify what. but with projectors using metal halide lamps, the lamps are under extremely high pressure, if you heard a pop then chances are your lamp exploded.
Typically the lamp ballast will try to strike the lamp three times, you should hear a buzzing sound, then basically fan noise then a buzzing, fan noise, finally a buzzing, then typically the fans will go to cool down mode and two minutes later your projector will be off.
If when you power it on, you do not hear a buzzing and if the lamp inside is still good, then your ballast is probably shot, but I would put my first guess on exploded lamp
mark, November 2010
