An Acer 5520 notebook.
Press power, the notebook powers on for a couple of seconds then powers off by itself. Then (without touching anything) it repeats the same power on/off cycle where the on is only a second) by itself over and over, until the battery is removed (which stops the cycle.)
Tried the remove battery/power charger and hold power on button for 45 seconds trick, but that didn't help. Charger seems to be working correctly (plugging it in lights the charge led).
Any suggestions?