What type of disc does my computer support?

I want to burn a movie in a dvd disc but my computer won't let me! I have the HP GC670AA cpu and it says it burns dvd but it wont work, everytime i insert a DVD-R in my computer, its like nothing happened. Isn't there supposed to be like a pop-out box that says burn files or open folder? There's NADA. Or should i get DVD-RW or DVD+R or DVD-RAM? what should i get?