I had a client whose computer would just shut down after three of for
minutes.. absolutely no warning, just a black screen and straight into the
re-boot sequence.. most of the computer internals were replaced with new and
more modern items, and the problem has not returned..
Another had a problem with a virus that was shutting down the computer, only
this time with a blue screen warning.. so both computers were shutting down,
but for very different reasons.. I ran a few programs, and all was fixed
without further incident..