Turned on my imac 2011 this afternoon and finder was not responding then system preference took ages to respond to the point I gave up. The disk utilities is not respondinG as well as the itunes displaing error -1712.

Turned on my imac 2011 27" and the finder seems to go missing, the disk utilities is not responding even itunes and system preference bothe are not responding. I have tried to reset to factory settings but the mac does not respond to the commands now the keyboard is not workinh too I am afraid thatif I keep turning on and off my boot up disk will be damaged too so don't know what to do it was working fine until this afternoon have tried taking off wires and connect them back but it seems to get alot worse however the screen still display everything that works like words and excel and safari works too. Has anyone had this before?