Removing the CMOS battery will not prevent the computer from turning on, it will only cause the information in the CMOS RAM to be lost (while the computer is turned off).
When you turn on the computer after the CMOS battery has been removed, while it will turn on it will most likely not boot the OS correctly but will stop in the BIOS and require you to completely setup the CMOS parameters again before you can tell it to continue..
I know that a BIOS password can be removed by opening the computer, taking out the CMOS battery and then turn the computer on. Turn the computer back off and put the battery back in. The BIOS password should be gone and you could do that in less than a minute if you were really good at it.
<improved answer>Just to correct the old answer, if the CMOS battery is dead, then the computer will not turn on in order for you to reenter it the next morning. It means that the CMOS battery is getting weak, and yeah, you could replace it. <old answer>It is most likely that the CMOS battery is dead. Replace it.
Read Only Memory (ROM) is not erased when you turn off your computer. There is a chip called the CMOS chip on your motherboard that holds all of the hardware information about your computer and other things as well such as the date and time. That information has to be accurate are your computer will not start properly. The motherboard has a small round battery called the CMOS battery it keeps about 5V of electricity always flowing even when you shut it off so that the data in the CMOS can be retained.ROM
(Computer should be turn off) To get to the BIOS/CMOS of the computer with you not knowing the password, first open the system unit, then take the CMOS battery and jumper out (refer to the motherboard documentation to locate the jumper) then set the jumper from 2 and 3 pins to 3 and 4 pins or from 1 and 2 pins to just 1. Put the battery back in, then turn on the computer, count to 20. Turn off the computer, set the jumper back to its original position then turn the computer back on, try to access BIOS/CMOS the password should now be gone.
CMOS battery of your laptop maintains hard disk, time and date, and other drivers and configuration settings in a CMOS memory. You will see these tiny CMOS batteries connected directly to the laptop’s motherboard.
Most times when the time never stays set after powering off one's computer, is an indication that the "CMOS" battery needs to be change. The "CMOS" battery is the little flat silver disc on your computer's mainboard that is responsible for storing all the settings including time and date. Note: Chances are though that when this battery goes out other settings will change back to default on your mainboard. Unless you are experienced with how to set your computer's settings, it would be advisable to let someone that is familiar with such things handle that for you.
Turn off the laptop, remove the battery. Remove the cover, and remove the hard drive and the CMOS battery. Count to 10 and put the CMOS battery back in the computer. Get a power drill with a 5/16 metal tip bit. Drill several holes in the hard drive, through and through. Get a new hard drive.
Most PC motherboards use a coin cell battery as a CMOS battery backup for BIOS settings. Most common battery used for this application is CR3032 and can be easily replaced. You can turn off the computer, remove power cables, open the machine and locate this coin cell on the motherboard and remove old battery from the socket with a plastic tool or your finger nails and then insert a new one in the socket. If using a metal tool/screw driver be careful that you do not short upper and lower side of the coin cell (which can cause a short circuit, can create a spark and will damage the battery).
Once the battery is replaced turn on the computer and resetting the CMOS values to the defaults. After the values have all been entered make sure to save the settings before exiting. Many CMOS setups allow you to press a key (such as F10) to save values and exit all in one action. If after following all the above steps you continue to experience the same error when your computer starts or your computer is still unable to keep the stored values it's likely that you're experiencing a more serious issues. Most likely causes are bad power supply or bad motherboard.
Take the battery out.
Remove negative battery cable. Turn on headlights. Wait 15 minutes. Turn off headlights. Replace negative battery cable. Better, go to Autozone, ask them to plug in their OBDII analyzer and hit "Clear". that way you do not clear the corrections the computer has added to the system and will have to relearn if you remove the battery cable. just remove the negative battery cable,wait 5 min,and put it back on,, computer will reprogram all by itself. Pre 1995 vehicles disconnect battery for 10 Minutes minimum Whats with turning on headlights with the battery cable removed? They will not work anyway
turn it off and go to a computer store to get it removed before it shuts down your computer