Clear CMOS: When and How to Reset Your BIOS

What the CMOS Stores for the BIOS

The CMOS is a small memory on the motherboard that keeps the BIOS settings alive while the PC is off. A coin-style battery on the board powers it, so the settings survive a full shutdown and even a short time with the machine unplugged. When you press the power button, the BIOS reads those stored values to bring the hardware up before Windows loads. The motherboard is the part of the PC that hosts this firmware and its memory, which is why the reset lives on the board rather than in Windows. Every current gaming platform, from Intel Core Ultra processors to GeForce RTX 50-series graphics cards, starts through this firmware handoff.

The stored values include the boot order, whether Secure Boot and TPM are enabled, how the memory is configured, and which controllers the board activates. A single conflicting value can stop the machine before it shows a picture. That is why a BIOS change that goes wrong usually appears as a boot problem instead of a Windows problem. Knowing this explains why clearing the CMOS works: it removes one bad value, not the whole system.

When a CMOS Reset Resolves Boot Issues

A CMOS reset is the right move for a specific set of symptoms: the PC powers on with fans and lights but no display, the machine cycles through repeated startup attempts, the debug LEDs on the board point to memory or boot, or the system refuses to start right after a BIOS settings change. A failed BIOS update can also leave the board in a state where the reset is the recovery step. Each of these points to the stored settings, not to your drives or Windows.

Before reaching for the jumper, confirm the trouble belongs to the settings. If the machine stopped working without any BIOS change, check the simple things first: is the display connected, is the monitor on the right input, are the power cables seated? Those checks belong in the troubleshooting a PC that won't boot guide. A boot loop and a no display condition each have causes beyond the CMOS, so they get their own walkthroughs too.

When a settings change started the trouble, clearing the CMOS removes the conflicting value and lets the board start with its safe defaults. The table below maps the common symptoms to the right first step.

Finding the Clear CMOS Jumper, Button, or Battery

Motherboards provide the reset in a few forms. The most common is a pair of jumper pins, often labeled CLR_CMOS or a similar abbreviation, placed near the board edge, the CMOS battery, or the rear I/O area. Newer boards sometimes put a dedicated button on the rear panel so you can reset without opening the case. A few boards place the button on the board itself. If the board offers none of these, removing the CMOS battery for a short time achieves the same result.

The exact position is in the motherboard manual, and on a prebuilt gaming PC the brand's support documentation for that model is the authority. Board makers print a label next to the pins precisely because the location varies with every layout. A rear clear button is the easiest method to reach; a board without one means the jumper or the battery is inside the case. The reset to defaults article covers the in-menu method, which is a different path from clearing the CMOS. The motherboard debug LEDs guide explains what those lights mean when the board stops early.

How to Perform the Reset

The reset procedure is the same idea regardless of the board: the machine must be off and unplugged, then the two jumper pins are bridged for a short moment, the button is pressed, or the battery is lifted out and returned. After that, power on and enter the BIOS to confirm the settings returned to defaults. The order matters, because the board clears the memory only while it has no power of its own.

With a jumper, move the small cap from its normal parked position onto the two clear pins, wait the length of time the manual states, move the cap back, and reconnect power. With a button, press and hold it briefly while the system is off and unplugged. With the battery method, remove the battery, wait, and reinstall it. The goal in every case is the same: wipe the stored settings before the board receives power again.

The machine may take longer to start on the first attempt after the reset, which is the board discovering the hardware again. If it still will not start, the cause is not the CMOS settings, and the next step is the boot troubleshooting guide.

What Resets After You Clear the CMOS

Clearing the CMOS returns every BIOS setting to the board's factory defaults. The boot order goes back to default, the date and time reset, and anything you enabled in the BIOS, such as a memory profile, Secure Boot, or TPM, returns to its default state. Windows 11 relies on UEFI with Secure Boot capability and a TPM of version 2.0, so after the reset it is worth reopening the BIOS and re-enabling those if the defaults do not already include them. The Secure Boot setup guide covers that adjacent step.

The reset does not touch your drives, your game library, or Windows itself. Nothing stored on the SSD or hard drive changes. The only things lost are the BIOS settings, which is the point of the reset. Afterward, reapply only the settings you actually need, such as the boot order or a memory profile, and leave the rest at the defaults.

If the machine starts but the settings do not stick, the problem is the battery rather than the reset. That is a separate procedure covered by the CMOS battery guide.

The CMOS Battery Versus the Reset

The CMOS battery and the reset jumper work together but answer different questions. The battery keeps the settings stored when the power is off. The reset clears those settings. If the machine loses its BIOS settings every time you unplug it, or the date and time reset on their own, the battery is likely near the end of its life rather than the settings being wrong.

A battery near the end of its life can make a board behave as if the settings were never saved, which can look like a BIOS problem. Replacing the battery is a separate task from clearing the CMOS, and the replacement guide walks through it. A fresh battery plus one clean reset usually brings the board back to a predictable state.

Clear CMOS on a Prebuilt Gaming PC

Prebuilt gaming PCs use the same motherboard concepts, but the reset can be less obvious. Some brands expose a clear CMOS button on the rear panel; others leave only the jumper on the board; a few rely on the battery method. The brand's support page for the exact model is the right place to confirm which method applies. Knowing where the reset sits is also a useful point to check when you read a prebuilt's spec sheet before buying, and the prebuilt buying guide shows what else a spec sheet should tell you.

If the board inside a prebuilt has no jumper and no button, the battery method still works, but the battery may sit under expansion cards, so plan to consult the documentation before reaching in. The reset result is identical: the BIOS returns to defaults and the machine can start again. For a new system, picking a board with a rear clear button makes future resets easier without touching the inside. The prebuilt checklist is a good companion for that decision.

What to pick for your play

Questions

Does clearing the CMOS delete my games or files?

No. The reset only clears the BIOS settings stored in the CMOS memory. Your drives, the Windows installation, and the game library remain untouched.

Is clearing the CMOS the same as resetting Windows?

No. A CMOS reset returns the motherboard firmware to its defaults. Resetting Windows is a separate operation handled inside the operating system. Each is done for different problems.

How long must the clear CMOS jumper stay bridged?

Only for a short moment, and the exact time is stated in the motherboard manual. The board needs enough time to wipe the stored settings while the power is off and the machine is unplugged.

Can the reset be done without opening the case?

Only when the motherboard has a clear CMOS button on the rear panel. Otherwise the jumper pins or the battery sit inside the case and require opening it. The manual for the board tells you which method applies.

Why does a failed BIOS update sometimes need a CMOS reset?

A failed update can leave the board with incomplete firmware settings. Clearing the CMOS returns the board to its defaults, which is often the recovery step a board needs before it can start again. The recovery guide covers that case in more detail.

Will clearing the CMOS affect Secure Boot or TPM?

It returns them to the board's default state. Windows 11 expects UEFI with Secure Boot capability and TPM version 2.0, so after the reset, reopen the BIOS and confirm those settings are enabled if they are needed.