Having Trouble Hooking Up Second Monitor

[Lemurfoot]

I've connected the second monitor(The brand/type is Viewsonic) to my PC via HDMI-DVI adapter (The HDMI end is plugged into the actual computer and the adapter end is plugged into the monitor). But it just says no signal when I turn it on, help?

 

[CustomBulids]

Does your monitor have a button that let's you change to a different source