Thanks again for all the tips. I did a fresh install of Windows, it starts 'normally' - but with vertical patterned puple lines across BIOS and flickering purple screens here and then. As I log in it does not seem that there is a video driver is installed as everything lags... when i start typing for Device Manager, the screen flickers, I hear a hardware disconnect sound and the external screen loses the signal from the PC. Now I get the BSoD on restart, same error as before. And still no sign of life from my laptop screen!
I will open up the laptop when I get a chance, as as you probably agree there's not much more I can do with software and drivers is there? It had a good 4 years life anyway!