Interesting. Hm. Stuck ctrl/shift/alt/swizzlestick key on the keyboard, or stuck button2 on a multi-button mouse?
You could be onto something there.
For example, I had to reboot my computer (not the accursed iMac, but a REAL computer

)just now to respond to this post because it was not registering any input from my Ctrl key. On the iMac, a stuck Shift key might have caused the symptoms I was seeing, although as much as I am not a fan of Apple, I have to say that their hardware is generally absolutely top quality.
I'll give that iMac another week or so tucked up high in the cabinet over the bed to make sure there isn't anything else on it that SWMBO might want to keep, then I'll nuke and repave it, and see if I can make it run using my old 22" LCD monitor (the iMac's monitor is failing) and if so, I'll put it up on the bulletin board at the Lake Chapala Society (that's the local Gringo hangout) and see if anybody'll give me $100 for it.
tanstaafl.