By golly, here I am again asking the same question AGAIN!!! I cannot seem to remember how to successfully trash the preferences in Illustrator CS3 PC platform. I tried moving the preferences folder, but I think there is one other thing that needs to be done... help!?!
Well, I don't understand it but it seems to be working now... Very frustrating problem this corrupted prefs thing. It seems to happen about every 6 months or so. Anyhoo, I'm back up and running for the time being.
The instruction are on Adobe's web site, you need to do a search for it, but it's there.
Another way is to hold down the alt, ctrl and shift key at the same time just before the program loads, this will reset most of the preferences, not sure it will do all of it, but most.