Tonight when using my three nifty case setup,,one of the cases froze up,,loads of lights on ,no sound,,i turned the power off and back on again,,it was ok for five minutes,,then froze again,,it was incredibly hot in my lab today,,can extreme external temperatures do this sort of thing,,or is the problem elsewhere?
If anyone can give advice it would be great,,thanks,,Bonehead.

too many modules, close to the limit, and it got hot
or
it got hot
or
it's broken

pull your modules, the power supply might be risky now,
and measure the three voltages with a scope/meter, then you'll know what's next

there's a possibility of a bad module pulling down power or a ribbon cable short too,
but i'd check the +12 -12 and +5, and avoid debugging by swapping things around too much