Well in a nutshell from what I have experienced, you cant.
It sounds to me that it is the mother board.
I have nothing but hard times trying to find a mother board for this machine...I have the same issues as you do.
And calling Acer support is really time wasting as they are no help.
All I can tell ya is that if it is still under warranty, you are in luck.
But if the warranty is expired, it would be best to have the machine put under diagnostics to see if it over heated...do what I did and see if it is the power adapter that caused it.
Mine smells like burnt electronics where the cord attaches to the three prong box.
I truly believe that Acer is ignoring a potentially dangerous problem and it needs to be brought to their attention before someone gets hurt.
nomoreacers, December 2004