If the computer has problems booting, errors during boot, or other abnormal problems that cannot be resolved try resetting the CMOS settings to the default settings as explained below.
One reason to clear CMOS is to help troubleshoot or solve certain computer problems or hardware compatibility issues. Many times, a simple BIOS reset is all you need to get a seemingly dead PC back up and running.
You might also want to clear CMOS to reset a BIOS or system-level password, or if you’ve been making changes to BIOS that you suspect have now caused some kind of problem.
1.Clear CMOS With the “Factory Defaults” Option
The easiest way to clear the CMOS is to enter the BIOS setup utility and choose to Reset BIOS Settings to their factory default levels.
- n CMOS setup, look for an option to reset the CMOS values to the default setting or an option to load the fail-safe defaults. With many CMOS setup screens, there will be a function key to do this. For example, the F5, F6, F9, F11, or F12 key, as shown in the picture, may be set up as a shortcut to load the default settings. Other setups may list an option that you can arrow over to using the arrow keys and pressing Enter.
- When found and selected, you’ll likely be asked if you’re sure you want to load the defaults. Press Y for yes or arrow to the yes option.
- Once the default values have been set, make sure to Save and Exit and not just exit.
2.Clear CMOS by Reseating the CMOS Battery
Another way to clear CMOS is to Reset the CMOS battery.
Start by making sure your computer is unplugged. If you’re using a laptop or tablet, make sure the main battery is removed too.
Next, open up your computer’s case if you’re using a desktop PC, or find and open the small CMOS battery panel if you’re using a tablet or laptop computer.
Finally, remove the CMOS battery for a few minutes and then put it back in. Close the case or battery panel and then plug in, or reattach the computer’s main battery.
By disconnecting and then reconnecting the CMOS battery, you remove the source of power that saves your computer’s BIOS settings, resetting them to default.
3. Reset CMOS using Software
There are a few software which can also reset CMOS settings or BIOS password or both within a few clicks. But as stated above you should have access to a system which is turned on and should have access to MS DOS or MS Windows:
4. Using Backdoor BIOS Password:
Some BIOS manufacturer put a backdoor password in BIOS which always works irrespective of what password you have set in BIOS. Its a master password which is used for testing and troubleshooting purposes.
AMI BIOS Passwords:
AWARD BIOS Passwords:
shift + syxz
PHOENIX BIOS Passwords:
Misc Common Passwords:
Other Manufacturer BIOS Passwords:
Biostar – Biostar
Compaq – Compaq
Dell – Dell
Enox – xo11nE
Epox – central
Freetech – Posterie
IWill – iwill
Jetway – spooml
Packard Bell – bell9
QDI – QDI
Siemens – SKY_FOX
TMC – BIGO
Toshiba – Toshiba
VOBIS & IBM – merlin