PC doesn't boot with new CMOS battery

omaroski wrote: When powering without battery and push the power button it powers on for a second then shuts off, then it restarts for 3 seconds, shuts off again and it restarts booting succesfully (don't know if it's a strange behaviour or it's supposed to work like this when battery is removed).

Yes, this is normal, with no battery installed if the system is disconnected from
power for any amount of time the motherboard needs to retrain the memory, this
is the off and on cycle you mentioned.

As for the new battery causing the system to not power on, what do you mean by that?
Does it turn on but not POST or does the power button do nothing? If it turns on
but doesn't POST, turn it on and leave it on for 10 minutes or so and see if it
comes on then. It could just be an initialization process taking some time, I have
seen it with new boards before, essentially your board is behaving like it's never
been used.