The built-in CD/DVD reader/writer in my G5 seems to have been working fine until I tried to install some software today. The DVD would be ejected just a few seconds after it was inserted. No icons would appear on the desktop. I tried inserting the OS disk and the same thing happened. Other CDs and DVDs that I have tried seem to work OK. I tried the same DVDs in my G4 PowerBook and they mount OK. Both the G5 desktop and the G4 PowerBook are at 10.4.9. Any suggestions.