Light on my sharp xg-nv4su projector comes on for a few seconds then goes off. how do i reset the lamp timer?

To reset the lamp timer you:
1. Turn off the main power button on the back of the projector.
2. Hold down the down, right, and enter buttons on the projector.
3. Turn the main power button on the back back on.
4. The projector should come on, hold down the buttons for at least 3 seconds after it comes on. If it doesn't come on, repeat the steps.
5. Turn the projector back off using the sleep button on the top of the projector. Then turn it back on. If it comes on and is functional, you have successfuly reset the lamp timer.

The lamp life timer may have expired. If the lamp blows as they can at the end of life, damage can be done as they run at high pressure. That is why they have a timer.