To clear CMOS there is an option to reset the configuration from inside the BIOS by going to the ADVANCED menu, selecting RESET CONFIGURATION DATA, and choosing YES.
It may be necessary, on occasion, to clear the CMOS settings by resetting the jumpers. This is most often required when a system is password protected, and the only person who knows the password is unavailable or has forgotten the password. When the CMOS is cleared, all information stored in the CMOS is replaced by default data, which means that all the configuration information, such as hard drive types and I/O port setup, is cleared at the same time the password is cleared.
Refer to the diagram of the system board and use the following procedure to clear the CMOS:

1. Power down the computer.
2. Remove the left cover of the computer as described.
3. Wearing an anti-static wristband grounded to the chassis, remove the jumper from pins 1 - 2 of the Clear CMOS jumper block (JP8) and install it on pins 2 - 3.
4. Leave the jumper on pins 2 - 3 briefly (approximately five seconds).
5. Remove the jumper from pins 2 - 3 of the Clear CMOS jumper block (JP8) and install it on pins 1 - 2.
6. Reinstall the cover and power up the computer.
7. Run the BIOS Setup program to reconfigure your system.