Hi,
That happened to me once. I reformatted the HD. When I tried to run a program, it told me I needed to have 256 colors then terminated the program. I went to control panel which told me I could select 16 colors or black and white. I discovered that I had to reinstall the graphic driver. Well, what driver and how do I identify it.
I went to
www.driverguide.com. There you can download trial version of a driver tool which will identify the hardward installed in your computer and give you enough information to identify your drivers. Use this info to find the right graphics driver or any other driver you may need for your computer.
It took me a couple of tries, but using the info provided, I got back all of the color choices for the computer.
Give it a try. Go to driverguide.com. Signup for a free membership. Find your drivers. Good luck.