hold Alt+F12 during POST
Ak potrebujes komplet navod tak tu je.

From a cold start with the power to the machine switched off press the power button and then enter the BIOS by pressing Del. Then when you get to the main screen press F9. This will bring up an extra screen which will display more information about the two BIOS versions. Assuming they are different exit the BIOS and shutdown. Again press the power button and this time press Alt + F12 where you would normally use the Del key to enter the BIOS. You will find that then your monitor will turn black and you will see:

Press [Enter] to start copying main BIOS to backup BIOS...

When you press Enter more text will appear saying:

Writing BIOS image.... xxxKb OK 

Once completed  more text will show: 

BIOS successfully recovered! Power off or reset system!