You get a CMOS checksum error during bootup. What is most likely the cause? A. power supply is bad B. BIOS needs updating C. CMOS battery is nearing end of life D. hard drive types are incorrectly defined E. None of the above

The correct answer is: C. CMOS battery is nearing end of life.

The CMOS battery is a small, lithium battery that is used to power the CMOS memory chip on the motherboard. The CMOS memory chip stores the BIOS settings, such as the date, time, and hard drive configuration. If the CMOS battery is low or dead, the BIOS settings will be lost and the computer will not be able to boot up.

The other options are incorrect because:

• A. A bad power supply would prevent the computer from turning on at all.
• B. A BIOS update is not necessary to fix a CMOS checksum error.
• D. Hard drive types are not stored in the CMOS memory chip.
• E. None of the above is the most likely cause of a CMOS checksum error.

If you are getting a CMOS checksum error, the first thing you should do is replace the CMOS battery. If that does not fix the problem, you may need to update the BIOS.