Want to print "as color" on a black and white printer

I have 2 black and white printers, and I want to print a color document.

1. When I print with one of them, the print preview shows me color, and the black and white hard copy it prints is to my liking.
2. When I print with the other, the print preview shows me a black and white document and the soft copy is not to my liking. This printer used to print like #1, but something caused it to change, I'm guess a driver update.

How can I force printer #2 to print like printer #1?

I am noticing this problem on Microsoft Excel 2010 on Windows 7, though I don't know if that makes a difference.