@vizoomer
Am not sure abt ny of my suggestion.

when u face Monitor problem try to open ur cpu and check the heat seeker{a meatl looks like steek below Gfx} of ut gfx card{grafic card}.

Abt Heet seeker - My experience is very but i guess gfx has two kind of seekers one a metal which seeks heet and another is that meal with a collers{fan}.

So if u check and fond itz too hot then u should try to change heet seeker with coolers.

For pc shutdown, try to change ur hard disk wiring "do't rember wire's name but there is a wire wich connects ut Hdd with Moth Bord".

I have also has encounterd same problem ehen i owned a pc with a atai graphic !!