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How to Perform a BIOS or CMOS Reset and Clear the NVRAM on Dell Computers

Shrnutí: The following article provides information about resetting the Basic Input/Output System (BIOS) for your Dell computer. This includes methods for resetting the Complementary metal-oxide-semiconductor (CMOS), the motherboard BIOS, and the BIOS without a display. This guide helps to restore your BIOS to default settings and clear the nonvolatile random access memory (NVRAM) on your Dell computer. ...

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Load BIOS to defaults

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Table of Contents:

  1. Introduction
  2. How to reset the BIOS from the BIOS interface
  3. How to clear the BIOS, CMOS, or NVRAM using a jumper on a desktop computer
  4. How to clear the BIOS, CMOS, or NVRAM by reseating the CMOS battery
  5. How to clear the BIOS, CMOS, or NVRAM on Desktop computers without an RTCRST Jumper or serviceable Coin Cell battery

Introduction

 

The information stored in the BIOS, known as the Extended System Configuration Data (ESCD), can occasionally become corrupt due to various reasons. These reasons include power events, incorrect settings, hardware incompatibility due to a specific setting, or a Power-on self-test (POST) or video problem. In these cases, it is sometimes necessary to reset the BIOS or CMOS to factory default settings. In other circumstances, clear the NVRAM or perform a Real-Time-Clock (RTC) Reset operation.

Warning: The BIOS interface is designed for advanced users. Be sure about the changes that you are making in the BIOS. Accidentally changing an unknown setting can prevent the computer from turning on, booting into the operating system, or can cause potential loss of data.

How to reset the BIOS from the BIOS interface

Note: This process resets the BIOS to factory default settings, but it does not clear the CMOS or NVRAM.
  1. Turn on the computer.
  2. Tap the F2 key several times until Entering Setup appears.
  3. Reset the BIOS to factory defaults. The method to reset the BIOS varies between different computers:
    • Click the Load defaults button.
    • Press the F9 key to load the default settings.
    • Press the Alt + F keys to load the default settings.
  4. Press the Esc key and select Save and exit or Exit.
  5. Press the Enter key to save all changes and exit the BIOS setup screen.
  6. The computer restarts and boots to the operating system.

How to clear the BIOS, CMOS, or NVRAM using a jumper on a desktop computer

Warning: Clearing the CMOS or NVRAM using a jumper resets the passwords in the BIOS. This includes the BIOS user password, admin password, and hard drive password. This does not include any other passwords such as Windows login, online accounts, and so on.
Note: The Real-Time-Clock Reset (RTCRST) and Password (PSWD) jumper is not available on all Dell desktops. For Dell desktops that do not have an RTCRST jumper, see the Dell knowledge base article: How to Reset the RTC to Recover Your Dell Desktop.
Note: The RTCRST and PSWD jumper are not available on Dell laptops.

The RTCRST jumper helps reset or clear the NVRAM on the computer. The ESCD information that is contained in the NVRAM can be cleared by following the steps that are mentioned below. The NVRAM is cleared when the jumper is set to the closed position and turning on the computer for 10 seconds.

Note: Dell desktop computers can be recovered from a turn on self-test or video failure by clearing the CMOS or NVRAM.
Note: The location of the RTCRST and PSWD jumper varies between different Dell desktops. For more information about jumper locations, see the User Manual Page of your Dell desktop.
  1. Before you begin, follow the: Safety Precautions When Working with Electronic and Electrical Equipment
  2. Turn off the computer and disconnect the power cable from the computer.
  3. Remove the computer cover. For model-specific information, see the User Manual of your desktop.
  4. Locate the 2-pin password jumper labeled PSWD on the motherboard.
  5. Remove the 2-pin jumper plug.
  6. Locate the 2-pin CMOS jumper labeled RTCRST on the motherboard.
  7. Move the 2-pin jumper plug from the password jumper to the pins on the CMOS jumper.
  8. Plug the power cable to the computer and wait for 10 seconds for the CMOS to clear.
  9. Disconnect the power cable from the computer.
  10. Move the 2-pin jumper plug back to the password jumper.
  11. Replace the computer cover. For model-specific information, see the User Manual of your desktop.
  12. Connect the power cable to the computer and turn on the computer.

Illustration of the PSWD and RTCRST jumpers on the system board of a Dell desktop

How to clear the BIOS, CMOS, or NVRAM by reseating the CMOS battery

The BIOS can be reset to factory defaults by reseating the CMOS battery that is connected to the motherboard. This process is applicable for both Dell desktops and laptops. Follow these steps if the PSWD or RTCRST jumpers are not accessible on a Dell desktop or if you are using a Dell laptop.

Warning: Clearing the CMOS or NVRAM by reseating the CMOS battery resets the passwords in the BIOS. This includes the BIOS user password, admin password, and hard drive password. This does not include any other passwords such as Windows login, online accounts, and so on.
Note: The CMOS battery cannot be reseated on all Dell laptops. For model-specific information, see the User Manual of your computer.
  1. Before you begin, follow the: Safety Precautions When Working with Electronic and Electrical Equipment
  2. Turn off the computer and disconnect the power cable from the computer.
  3. If you are using a Dell laptop, disconnect the battery from the computer. For model-specific information, see the User Manual of your computer. If your Dell laptop has a nonremovable battery, see the Dell knowledge base article: How to Reset the Real-Time Clock (RTC) to Recover Your Dell Laptop
  4. Remove the computer cover. For model-specific information, see the User Manual of your computer.
  5. Locate the CMOS coin-cell battery (Figure 2 and 3).
  6. Carefully, disconnect the coin-cell battery from the motherboard.
  7. Press and hold the power button for 10-20 seconds to drain residual power.
  8. Connect the coin-cell battery to the motherboard.
  9. Close the computer cover.
  10. Connect the battery and the power cable to the computer.
  11. Turn on the computer.
  12. A warning message appears indicating that the date and time is not set.
  13. Press the F2 key to enter the BIOS screen.
  14. Set the date and time according to your time zone.
  15. Save and exit out of the BIOS screen.

Illustration of a coin-cell battery on the system board of a Dell desktop

Illustration of a coin-cell battery on the system board of a Dell laptop

How to clear the BIOS, CMOS, or NVRAM on Desktop computers without an RTCRST Jumper or serviceable Coin Cell battery

If your desktop computer was produced before April 2020, the computer most likely has a jumper-based reset. Desktop computers manufactured after April 2020 use the RTC Reset ability.

Note: Desktop computers released after April 2020 should have RTC Reset enabled by default.

For desktop computers that use RTC Reset, hold the power button for 30 seconds.


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Vlastnosti článku
Číslo článku: 000124377
Typ článku: How To
Poslední úprava: 10 Oct 2024
Verze:  27
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