How do I Enable My Integrated Video Card Again?

I bought a video card 2 days ago and it was the nvidia geforce 8600 gts. Everything went great until it needed power. I still need to buy a power supply but i tried it without power and it still worked. I saw forums saying not to do that because it will cause damage. When i inserted the card into my motherboard and powered up the computer i had to install the drivers. Once i did that i disabled my old video card (It is integrated into the motherboard) and it automatically used the new one. I need someone to help me enable my old integrated video card because i really don't want to damage my new one.|||Just take out new one,and connect your monitor (VGA) cable to your integrated graphic card on back of your computer! Uninstall drivers of your nvidia gforce 8600 drivers and install the drivers of your integrated video card!