Because it is a DOS tool, you must create a bootable environment to use it properly:

Insert the drive into your locked Acer laptop and restart. Tap F12 during startup to select the USB as your boot device.

Note: If F12 is disabled and you are locked out of the BIOS, you may need to temporarily remove the internal hard drive to force the system to boot from the USB.

If you are locked out of your Acer laptop's BIOS, searching for is a common first step toward regaining access. clnpwd.exe is a specialized DOS-based utility primarily used to clear supervisor, user, and HDD passwords on older Acer hardware. What is clnpwd.exe?

The ( clnpwd.exe ) is a legacy tool designed to run in a DOS environment to reset CMOS-stored security features. While users often search for a "64-bit" version, the original utility is a 16-bit DOS executable . This means it cannot run directly inside a modern 64-bit Windows environment like Windows 10 or 11; it must be launched from a bootable DOS drive. How to Use clnpwd.exe

Copy the clnpwd.exe file to the root directory of your bootable USB.

Use a tool like Rufus to create a bootable FreeDOS or MS-DOS USB flash drive.