The manual of your motherboard should tell you how (what keys to press) to get into the BIOS setup when booting. You can't use the mouse to get into the BIOS, but possibly you can use when in the setup.The keyboard (if it's a USB keyboard connected to a USB-port on the motherboard) should work (unless the mono-manual says it must be a PS/2-keyboard, but that's unlikely).
Why do you think you need to go into the BIOS to install an OS?
Kees
I recently bought a new computer and built it myself. I do not have an operative system yet, so i need to get into bios to install it. I've tried every f-button, del, esc and every combination i can find on the internet. The problem seem to be that the keyboard and mouse can communicate with the motherboard or so. Both of them is getting power, but it wont work. I do not have a Serial port connecter (COM?), do i need it to be able to communicate? Both keyboard and mouse is USB.

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