I have tried putting all the old cartridges back in and I have been using non Brother brands fro a few months from Meritline.com(much cheaper!). I have tried turning off the power for a few minutes, but it goes right back to the same Black empty screen. It seems like it is now unable to detect a cartridge in the black section-the other colors seem OK. Thanks!
I looked at the locations you noted and I don't see any obvious problems. It puzzles me that the Brother cartridge was initially working fine and within a week it said it was empty. It is a new printer for us since we got it in August 2008, but it was refurbished. If you think it's a lost cause, I will just purchase a new printer and write this off as a loss. Thanks!