|ALL: SEE also his other post:|
Though this adds something else to the question, it does not include enough details and there are wild speculations about one thing being related to something else.
IS this a new computer? Have you had it long? Is this a refurbished machine? Is this a hand me down machine? Was this machine at anytime part of a corporate network?
If this machine was not new when you got it, you may need to do a Factory Restore which will return it to the way it was shipped from the factory (Please note that all data will be lost so if you have anything to save, do this to an external drive before proceeding.).
You have to be a little bit crazy to keep you from going insane.