[X-Newbies] Video DVDs

[Keith Mills]

Hello everybody. I've not seen anything on this list for some time, but let me try.

I am using iMac 10.6.8. 

Until recently I have been able to use it to watch video DVDs. But now suddenly it is ejecting the DVD. I have looked into System Preferences and next to: When you insert a video DVD, it says - Ignore.
I have clicked on Open DVD Player, but it just returns to Ignore.

Many thanks in advance.

Keith Mills