Pavillion zv5000 won't start

I have a zv5000 that will start sometimes, and sometimes is won't. I have read the other posts and tried a hard restart, removing the battery and running, unplugging the adapter and running. They work but after the computer starts and runs for a while, I will shut down and try and restart and sometimes it will restart and sometimes it won't. I thought it might be the battery overheating but it doesn't seems to make a difference where I put it.
Any advice?