DVD ROM Drive Won't Allow Access To DVD ROM Features

I have been in the dark ages of technology but recently purchased a Dell Dimension 3000 Series Desktop. It is the first time I've ever had any experience with a DVD ROM drive, so I'm not sure what I'm doing wrong. I tried to play a 2-disc DVD set that is supposed to have enhanced computer features. When I insert Disc 1 everything works correctly. It will play the movie like on any DVD player, and it will also pop-up a special DVD ROM menu and allow access to the special features on Disc 1. However, when I click on most of the special features they tell me I must insert Disc 2, which I then do, but the second disc will only play as a regular DVD and will not allow access to any DVD ROM features or the DVD ROM menu. It is extremely frustrating because I have no idea where to even begin to correct this problem, and it seems unlikely that there would be a compatibility issue or need for an upgrade when it will play one disc from the set but not the other. But, as I stated, I have no idea about this kind of technology. My DVD ROM is Sony DVD-ROM DDU1615 and I'm using InterActual Player 2.6 I went to the support website for the actual DVD, but it merely informs me that if I'm having trouble accesses the the DVD ROM features I will need to install the lastest version of Macromedia Flash player and have Apple QuickTime version 6 or above. I have all of these components and don't understand the problem