dual monitor

[devonian44]

I am struggling to set uo a second monitor
on Sony Viao .I have got a mesage telling me that it is not enabled. But I cannot find how to enable it.Can anyone help?
Thanks

 

[DoubleHelix]

Can you be more specific? Is this a message from the operating system? The Vaio line applies to both desktop and laptops. Which do you have? What specific model?