Another site with very helpful members in the forums is DPC
http://www.dpchallenge.com/index.phpIn the short term, you might try removing the battery, removing the lens. Clean the electrical contacts on the lens (carefully) with a pencil eraser. Clean the contacts on the battery, as well--probably not the problem, but it can't hurt to try it.
Then put the lens back on the camera, install a fully charged battery.
Sometimes a bad connection, or the electronics in the lens can "hang" the camera, so it might not actually be turning off when you think it is. That is about the only thing I can think of.