Open your System Preferences (either from the pull-down menu under the Apple icon in the far upper-left or from your Dock), then under Hardware there is a "CD&DVD" button. Click that, then you can choose what you want your computer to do when you insert a disc. It may have "Ignore" chosen as the default. You can choose any application you want to open (like DVD Player) or to have the disc icon just show up n the Finder when you insert it.
When i insert some discs into my optical drive, they don't show up in finder, and won't play in DVD player. i looked in my disc utilities, and it sees the dvd there. I can play the dvd in VLC player, but i can't access it in other programs. the same problem is happening with some data dvds i've burned, however, some still work. Any clue what's going on?