This works. Here is what I did.
How To Reset Panasonic LCD Lamp Timer:

Step 1: I turned the volume all the way up.
Step 2: Hold the Volume - button on the TV (Not the remote) until it
was at 0. Keep holding the Volume - button down.
Step 3: Press and hold the PIP/Play button on the remote until the
message shows the timer has been reset to 0.

Hole that helps.

wrote:
I have a Panasonic PT-45LC12 LCD rear projector TV. I just replaced the
bulb and tried to follow the instructions to reset the lamp hour meter;
i.e., hold down the TV's Volume-- button while pressing the remote's
PIP/Play button. It didn't work...even after several attempts, and
after unplugging the TV from the wall socket and reconnecting. Any
suggestions would be appreciated for solving the problem, or am I just
stuck with a TV that doesn't obey commands anymore?