My DVD reader doesn't always load....

Hi all, I appear to have a problem with my DVD reader (Gigabyte Technology 16x16 DVD rw/r). When I put a dvd in the tray, sometimes the DVD title comes up in the "recent device" window, sometimes nothing. When "nothing" comes up, sometimes the tray is locked & I can't get the disc out again. I have a pair of DVDs, produced in Germany, one plays, the other doesn't..... If the disc loads, sometimes I can play it with Kaffeine, sometimes I have to use Bangarang, because Kaffeine doesn't see any start point on the disc..... Then one time, Bangarang plays one disc; when I try to play a second one it crashes.... Anyone got any suggestions on how to try and debug this little lot????? As ever, many thanks for any help you can give me!!!! Cheers Dave uname -ar Linux Fedora-Blue 2.6.35.11-83.fc14.x86_64 #1 SMP Mon Feb 7 07:06:44 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux KDE, MSI880GM-e41 with Phenom II X6 1075T