When pressing the start button the Hard Drive indicator flashes momentarily but doesn't startup. Let set for a few days and it will startup normally. Stays running till I shut down with Windows. Try to startup again and it will not start and I have to let sit for several days. Then it will startup and operate normally again. Doesn't seem hot. My battery is old too but will hold a little charge. Doesn't make any difference if it's on AC or Battery. My first impression is that it starts only on a low battery because every time it DOES start I have to switch to AC shortly after. I can shut down and restart multiple times on the low battery but once it's charged up it won't start. I thought it might be the hard drive but it should start to the BIOS even without a Hard drive. The CPU comes to mind but I don't have replacement to try.
Memory's good, I have a new battery and AC power supply.