1150 powers for 3-4 seconds

Hi can anyone help, I have a Insp 1150, when I try to switch it on all the devices come on  the caps lock flashes green and the front left light comes on, then after about 3 or 4 seconds it all shuts down.

 

I have tried reseating everything and have tested all removable items on my girlfriends 5150, they all work fine on that.

 

Also tried starting with mute button pressed, dont know what it does but it was suggessted on a different tread.

 

Many Thanks