This afternoon my color laser printer stopped printing color. Black and white only. So I Google searched for "HP CP2025dn color laser printer only prints in black and white" and sure enough, there was a match to my exact search.
I followed the link, and to my surprise it led to a thread on something called the empeg bulletin board, and a poster by the name of tanstaafl. had had the exact same problem about 15 months ago, and figured out for himself that the solution was to delete the printer and reinstall it with a replacement driver.
I tried the same thing, and it worked.
That tanstaafl. must be a pretty clever fellow.