How to Clear CMOS on an ASUS Motherboard

If your business or home computer refuses to start up, especially after changing any of the basic boot settings or updating firmware, you may need to reset settings in the basic input-output system or BIOS. Sometimes, you can do this using the menu prompt when the computer starts up, but if even this isn’t accessible, you may need to reset a small section of memory known as the CMOS. You can reset the CMOS on an ASUS motherboard by wiring together particular pins on the motherboard.

Understanding BIOS and CMOS

Most modern computers have what’s called a basic input-output system, or BIOS, that loads even before operating systems such as macOS, Linux or Windows. The BIOS helps the computer’s central processing unit communicate with memory, hard drives and other installed devices and keeps track of basic data like the system time and boot settings.

It stores that data in a small area of memory commonly called the CMOS, for complementary metal oxide semiconductor, a technology often used to build that area of memory. It’s sometimes also called the RTC, for real-time clock, since it also stores data about what time it is, even when the computer is off. Generically, it can also be called NVRAM, for non-volatile random access memory, referring to the fact that it isn’t changed by rebooting the system. On a Mac, it’s sometimes called parameter random access memory, or PRAM.

Dealing With BIOS Issues

If some of your BIOS settings are incorrect, you can often fix them by entering the BIOS setup menu as you boot your computer. This will allow you to change the order in which your computer looks for devices to load an operating system from, which can be helpful if you want to boot from a DVD or a USB stick instead of your hard drive, and update settings related to installed devices and even the date and time.

When your computer is starting up, look for a prompt to press a certain key, such as F2, F8 or Delete, to load a BIOS setup menu. If you don’t see such a prompt, check your system’s documentation. If you don’t understand a setting, ask for help, contact the manufacturer or another expert. Take notes of the changes you make, and don’t make changes at random, since you might have trouble getting your computer to start up again.

Reset CMOS on ASUS Motherboards

If you can’t make the changes you need through the BIOS settings, you can’t access the BIOS menu because it’s locked with a password you don’t know or the BIOS menu won’t load, you may need to reset the CMOS memory. On an ASUS motherboard, this is a technical process that requires you to open your computer. If you’re not comfortable with tools and electronics, you might want to ask for help or take the computer for professional servicing.

Turn off and unplug your computer. Open your computer’s case with a screwdriver, keeping note of what screws go where. Find your computer’s motherboard and look for the CLRTC jumper, a set of two pins on the motherboard. The ASUS motherboard jumper abbreviation CLRTC stands for “clear real-time clock,” since it’s used to clear the RTC or CMOS.

Then, with a screwdriver, wire or other metal conductor, connect the two pins. Make sure the conductor isn’t touching any other components or yourself. Plug the computer in and turn it on. The CMOS should be reset, and you should be able to hold down the appropriate key to enter the BIOS menu and enter new settings.

When you’re done, turn off and unplug the computer. Remove the conductor and put the computer back together. Start it up normally.

Removing the Battery

If the CLRTC jumper doesn’t seem to clear the CMOS, you can try removing the battery, which is usually a round battery similar to a watch battery. Turn off and unplug the computer, open it up and remove the battery. Connect the jumper pins again.

Boot the computer and verify you can enter the BIOS menu, indicating the CMOS is cleared. Then, shut it down, reconnect the battery and seal the case. Boot the computer, use the BIOS menu to set appropriate settings and use the computer normally.

If this process doesn’t help, contact ASUS or your computer’s manufacturer for help.