In addition to above suggestions: in auto-iso, set minimum shutter speed appropriate to your focal length.
In low-light conditions, set aperture wide open (f1.4-f2).
First thing to try would be a factory reset.
If the camera locks up before you can select it in its menus, it is still possible clear its settings-memory (cmos?) by leaving it without battery for a while. Actually don't know for how long you would need to leave it, as I accidentally discovered this option by storing my camera for a year (wanted to have it repaired for a similar lock-up problem, which turned out to not be necessary after all ^_^).
You will know the memory was cleared when you have to re-select language and date+time when starting it again.
Hello 10 years later... So what I did is I cut the inner structure so it doesn't have to fit inside the body. Then I used a double sided tape. Poor camera even doesn't have a working screen. Or is it happy because I still care about it?
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