How to Reset an eMachine BIOS
The BIOS (Basic Input/Output System) on your eMachines computer is the firmware used by the motherboard to run the POST (Power-On Self-Test) when the system starts up. You can configure the BIOS to recognize hardware, enable and disable system components and monitor the system. If, in the course of testing BIOS configurations, you find that you have rendered your computer inoperable, you will need to reset the BIOS back to the original factory settings. Fortunately, there is a keyboard command built into the eMachines BIOS interface that accomplishes exactly this.
Restart the computer if it is on or press the "Power" button to turn on the computer.
Press the "Tab" or "Del" key to enter the eMachine system BIOS. Older eMachines systems may require that you press the "F1" or "F2" key instead. If none of the listed keys work, watch the screen while the computer boots up for a message indicating the correct key to press to enter the "System Settings" or "BIOS Settings."
Press the "F9" key to load the default BIOS settings, which will reset all of the BIOS settings back to the original "factory" configuration.
Press the "F10" key to save the BIOS settings and exit the BIOS interface. The eMachines computer will reboot and start up using the default BIOS settings.