I too have a P600 with both the same problems. I had to send it in under warranty to get it repaired. They replaced a flex circuit board and switch. That worked for 6 months and now it will not turn on. Out of warranty now. I need to send it in or try to fix it myself. In looking at the "lens replacement" link I may try it myself. It appears that it maybe nothing more than a flex circuit that became disengaged. The quote for the last repair was almost $150 but that was covered under warranty. So I may need to send it in again. I do know that I will never buy a Nikon again. I expect quality with the Nikon name and Nikon has not delivered.