I used to have an A1200T in the original version of the Micronik case (the mostly plastic one). The Zorro II backplane was very flaky. If I moved the case even a little bit, the system would lock up and on the next reboot cards would be "missing" from the system. What I would suggest first is removing all the cards and simply reseating them in the same slots. Do that with the power turned off, of course. Then try powering up and see if your problem is gone.
