Determine whether your computer has a DVI (digital video interface) card installed. If not, install one or buy an external DVI card.
How do I tell if I have this? Do video cards come with that normally? Mine has a 1024MB ATI Radeon HD 5770 GDDR5. It also has a HDMI to VGA adaptor but I don't think that has anything to do with what ehow is talking about.