What I find are many folk unaware about 300 cycle batteries and how an old battery can tax or even fry the motherboard. Your story is incomplete. How many years old is this battery and does it work without it?
I have an Acer Aspire 5520. When I turn it on, it starts to power up for about 3 seconds, then turns off. It cycles through this endlessly unless I remove the battery. If I put the battery back in, or connect the power cable and turn my laptop on, it does the same thing, till I remove the power source.