Ok guys, hers a triky one
apparently the computer was working fine, then half way through the boot sequence it faded away until there is nothing on screen.
My first thought was the monitor so i swaped the monitor for an old on i have.
That didnt work so i thought new graphics card (At the mo its a Vodoo 3dfx chip) so in goes a new card.
And now i'm stuck
I think this one is dead