Many thanks to all who suggested solutions to my cursor freeze in the top left corner upon boot up. Unfortunately none of the ideas worked. The real cause which I eventually found myself was a failed power supply to the Banksia USB hub. Zero reading on the output of the power supply when it should have been 5 volts DC. Now I should have seen this long ago because the hub has a little light to indicate power, but being usually covered with stuff, and my ignorance of what was normal, I failed to twig when I should have. The Imac did also manage to flash a few LEDs when using the hub, which is what deceived me.
The original power pack claims a rating of 2.8 amps but is a real physical lightweight. Chinese electricity must be thinner than Australian. So, I thought, all this needs is a new, cheap 5 volt transformer pack from someone like Dick Smith. No such luck. It is an odd voltage. 6 volts being the closest, which might have been okay. Even so it is twenty percent over voltage for the device, and I could be embarking on a $25 or more gamble. Eventually I bought a new Belkin hub pack from Harvey N for $49 and the problem is solved. Plenty of lights glowing at me now on boot up, and the cursor is free at last. Another victory of a man over a machine. Regards, Paul.
