battery on 2004 Pontiac Grand Am

if my battery is bad and can not hold a charge will that keep my car from cranking. the reason i ask is I tried to start my car would not start and even when I charged it. Can this cause me to have to reset the computer in it? Or how will this effect the computer in it? I tried to hook up to the computer but the battery didnt have enough power in it. I am going to buy a new one just curious on how this effects it.

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The computer in your car needs a minimum voltage before it will operate normally about 9 volts. A fully charged battery should have a standing voltage of 12.6 volts and pass both a hydrometer test and high rate discharge test (its a load test). A sulphated or bad battery will not hold a charge and may even have an internal open or short within the battery. Put a volt meter across the battery terminals with the engine off, at rest the battery voltage should be 12.6 volts if the battery is fully charged. Now get a friend to start the car while you watch the voltmeter, the voltage reading across the battery should read approximately 14.6 volts if the alternator is charging correctly.
I turned the key on and off not rapidly but enough to let the light come on then off 3 times and then the fourth time tried and start it. It sounded terrible for a sec but cranked right up. I waited a bit and cranked it again no problem. I am a little stunned it worked but it seems to be running fine now. Except for the tension pully bearing sounding like crap. But I can replace the easy.