Accessing the BIOS Setup HP Pavilion g7

Hello, I recently bought a Windows 8 computer and I would like to change that...
I found a very effective tutorial but to do so, I need to access my BIOS (UEFI) at startup of the computer.

I have tried everything so far and I have done a lot of research too...
Several sources said to press F10 at startup of the computer (In my case: Fn + F10 - I tried just F10) In any case, it didn't work!

I did this manipulation during the startup screen: An HP icon in a blue circle with a loading circle below.
Like here, except instead of blue rectangles, I have the HP brand.

Thank you for your help!

Configuration: Windows 7 / Chrome 26.0.1410.64

// Crazy-Levon // Psico-Al3xX // Pake // At your service!