.
All of you have given helpful and potentially useful recommendations, but noone has yet mentioned the most likely cause:
Posession by evil spirits!
That's right! These chips are now so complex and intelligent they can indeed be posessed by evil demons. This is the only conclusion I can come to after all the years I have dealt with intractable computer issues.
The only solution is digital excorscism or execution, followed by rebirth and resurrection.
(ie., trash it and get a new machine)
Hope this helps.
.