Here is what I have, I have a Folger Tech Prusa I3 and wanted to upgrade to a full graphics view. I watched and tried to follow both written tutorial and videos with no luck. I have installed the U8glib.
You have to uncomment the line in Marlin's Configuration.h file for that device, as well as tell the Arduino toolkit to include u8glib. Recompile and download to your Mega, and it should work.
Its worked. I downloaded a fresh copy of marlin. I guess I had changed so many setting in my old config file that I had it all screwed up. Thank you for your response.