Please choose the correct ending to complete the given sentence: Computers and Electronics: [header] How to install dual video cards [title] Ensure that your motherboard is compatible with dual video cards. [step] Either check your motherboard's manual, or, if you don't have that, find out what model it is and check the manufacturer's web site. [title] Unplug your computer system.

Ending1: [step] Feel free to unplug it from the pc and eye cables. [title] Plug the motherboard into the computer's power source (the ram) or socket. Ending2: [step] It can be taken off of a usb drive or plugged in to another computer while you are using the computer as your primary computer. [title] Boot from your start command prompt to the start-up windows setup menu. Ending3: [title] Remove the side of your computer case or the whole cover, depending on how your case is configured. [title] Locate the two pci express slots where you will be inserting your video cards. Ending4: [step] Leave the power running, and shut down your computer for at least two hours before proceeding. [title] Find the d-pad and make sure it is securely plugged into a wall socket.

Answer format: ending1/ending2/ending3/ending4