The CMOS (Complementary Metal-Oxide Semiconductor) or motherboard battery works as an RTC (Real-Time-Clock) on your motherboard. The CMOS acts as a battery-powered semiconductor chip inside y. Corruption of CMOS is unfortunately very common. The average lifespan of CMOS batteries is 3 to 10 years. If you use your computer more often, the battery will last longer. If you go. Although the battery can outlive the usability of the system, it does fail over time. Here are a few signs that point to a failing CMOS battery: 1. The computer is refusing to boot t. To verify that the battery is the issue we will need to narrow it down. We can try first by resetting the CMOS. After that check if the battery is dead using a multimeter and then replace it with a. Technically, YES. Removing the CMOS battery will allow your computer to run however, you will lose the date and time settings, the computer will boot with default BIOS settings or.