Brother 420cn mfc, cant print It asks me to read in the routine maintenance of the trouble shooting guide.

Did you use non-Brother brand ink refills? If so, the print head is probably clogged. If that is the case, it's almost cheaper and easier to replace the printer itself. Sorry. I loved my MFC-210C until it quit, and the internet is full of people complaining about the whole MFC series. Going on 2 trouble free years with my Canon, better print, better optics, wireless, but no fax, unfortunately.