Since we specialize in repair, we see and here about all kinds of camera problems. Both the Canon 5D Mark II and Mark III have been known to show an “Error 30, 40 and 80” code on the top LCD window, which is usually memory card related?
In general, when your camera locks up… the first thing you should do is turn the camera off, take the battery and memory card out of the camera (which will force the camera to reset) and then put the battery back in, turn it on and see if the camera works. If you have access to the menu settings, you can downloading the latest firmware version (found on Canon’s website) and update your camera in hopes it was a software related bug that Canon fixed after production.
If the symptoms/ error codes still appear, the camera will most likely need to be taken apart and repaired or at the least, reprogramed by computer. If you are experiencing any further problems, please contact us at firstname.lastname@example.org or stop by with your camera and let one of our repair technicians check your camera out.