Display Adapter?

Hello..
1) I have a standard VGA video card. I cannot adjust the color beyond 16 colors. I thought I used to be able too. Am I limited with this card, or do I need to upgrade to 256 and true color.
2)Also, I switched monitors, and all xxxx broke loose. I fixed it and went back to the old monitor. Tell me about a book or website on diganosing conflicts, and resources and adding and removing hardware.
3) I thought I could just switch monitors without adding and removing the driver…Is that so?
Thanks…….Pat