The reason you can't get any more colors from the internal video is because you didn't install the driver for it. You must install the video driver or you only get 2 or 16 colors.
You will have the same problem if you install another card and don't install the driver for it, unless the video driver is built into the version of Windows you have.
In order to use a different card with many systems you must disable the onboard video in the Bios, but some systems don't even permit that. Have you gone into the bios and looked for an option to disable the on board video?
You didn't tell us a thing about your hardware or version of Windows, so we really can't give specific instructions.
MMy incorporated video card would only give me 2 and 16 calor. I wanted to put in a new card. I clicked remove video card from device manager. I shut down my computer, installed a new card. Surprise, i can't see anything on my screen. is there any solution to this.

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