How to distinguish the computer to belong to VGA+DVI and so on?

My computer is quite old, is others assembles for me.How distinguishes my computer belongs to VGA+DVI, double DVI or is DVI+HDMI and so on?
Looks at behind your engine case, if has the white rectangular attachment, the belt is thin the strip hole, that is dvi.If has trapezoidal blue color belt 15 small round hole attachment that is vga
Looks at this chart:
http://image..com/i?ct=503316480&z=3&tn= imagedetail&word=dvi&in=12134&cl=2&cm=1&sc=0&lm=-1&pn=13&rn=1&di=2430856536&ln=1807
The left side is vga, right side is dvi