DellA920 Printer: Color does not print. Do I need a new print head? Is it difficult to replace?

First, do not put all of your problem in the Subject. All you would have needed is what I left in the Message Subject (it's limited to 100 characters, anyway).

Are you getting any "low ink", "out of ink" or any other message?  If not, remove the Color cartridge (your manual will tell you how) and soak the nozzle end in a shallow container of warm, not hot, water for about 10 minutes.  Blot dry, reinstall and try a print.  If the nozzles were just clogged this will fix it.  If not, you will need to buy a new Color ink cartridge (make sure it's the correct part number).  Dell's are available at most Staples and Wal-Mart's.