Solution:

When the “Clear” button is pressed with the “Reset” button, any configuration changes you may have made through the switch console, the web browser interface, and SNMP management are removed, and the factory default configuration is restored to the switch. 

Specific steps to execute the factory default reset on the switch are:      

1. Using a small, thin tool with blunt ends (such as a paper clip), simultaneously press both the Reset and Clear buttons on the front of the switch.

      2. Continue to press the Clear button while releasing the Reset button.      

3. When all three Mode LEDs (Act, FDx, and Spd) begin to blink, release the Clear button. 

The switch will then complete its self test and begin operating with its configuration restored to the factory default settings.

Note: After completing this procedure, there will be no password, the IP address will be returned to the default 192.168.2.10, and all configuration settings will be returned to factory defaults.

Quelle: HP Support Center