I am running Win XP and have a Canon BJC-6000 printer. The printer has stopped printing black. I have changed the ink cartridges. In fact I just changed all the color ones and the Black one. Still the black will not print. It goes the the motions of printing a document, picture, etc. but the only thing that works is if I change the text color to red or blue or some other color. What can be the problem? I went the the printer diagnostics....head cleaning, deep head cleaning...you name it....but still no black...WTF? These are BRAND NEW authintic Canon ink tanks. Any help will be apprectiated....Thanks