I tried to press F1 during Start-up, but this doesn't allow me to get into the BIOS.
Ensure that your Windows 8 machine is completely powered down.
When you click shutdown regularly, Windows 8 doesn't really shut down the laptop completely, but puts it into hibernation state. This is called "hybrid shutdown" so as to allow a quicker subsequent Windows startup.. When shutting down, hold down your shift key while clicking shut down. This should power your machine all the way down.
When you start the computer back up, immediately start hitting the enter key to go to the interrupt startup menu.