Think he has sorted his problem out, hopefully.
As I put in my original post
just as if the graphics card was disconnected
And as Simon suggested, by re seating the card.
It turns out that even though the card is held securely with the clip at one end of the board, it is in a new fancy case that has sliding plastic clips pushing down onto the metal bracket at the case end instead of being screwed in.
It has screw holes provided but the plastic clips get in the way when you try and use a screwdriver so I suggested that he breaks the plastic clips off and uses screws as normal.
The strange thing is it must not have come fully out as it would work ok after a reboot, until tonight when it didnt and when he checked he could see it was cocked up at one end