hello, at CP2000 you have two (2) hard disk. Number one is the main disk, number two is the back-up disk. There is a small black switch on top of the computer in the CP2000; machine must be OFF; switch from Disk 1 to Disk 2. In most cases, this switch is marked with a seal, a plastic sticker. This is one option if there is a hard disk - Error. On the other hand, you have to check the Heidelberg Service menue, just to find out whats the main problem. I GUESS THIS IS A ELECTRONICAL PROBLEM - T - is showing me problem at MAIN CABINET 91. Switch to the Feeder section, the Feeder menue and show us the error messages.