1. Maybe driver for this video card is missing. To find the make/model of your video card, you might want to you use PC Wizard which is a free program available at http://www.cpuid.com/softwares/pc-wizard.html
Once you are able to find which graphics card you are using, you can easily download driver from manufacturer's website.
2. Hope you are aware of the Windows 8 built-in option for Second Screen
Press Win+K (Windows key and "K" together) and you would see second screen option and you could go from there.
Hope that helps.