Laptop screen and Vizio monitor both as dual screens for my desktop

Note:

Laptop: Dell, Windows 7

Desktop: HP, Windows 8

I have a monitor connected to my desktop using a VGA cord. The desktop has two of these VGA ports, so I simply connected my laptop with 1 VGA port to my desktops second VGA port. Both computers were turned off when I did this. I turned on my desktop first (because I want to use it as the computer) and logged in, and then I turned on my laptop. My laptop started to boot up Windows 7 then it made the sound you get when you get to the Windows log in screen but my laptop screen isn't displaying anything. I tried to access the "Display" setting in:

Control Panel\Appearance and Personalization\Display\Screen Resolution

I could not find the second option in the "Display" drop down.

I want to run my laptop screen and Vizio monitor both as dual screens for my desktop