NEC 4550A - Won't read some DVDs

Drive reads all media except original Region 1 DVD movies and also DVD Game Rom of Silent Hunter 3 . These discs are not detected. Region 2 DVDs work fine.

Latest Drivers & Firmware installed. Tried region change to Region 1. Now using RPCI firmware. I’ve tried removing all burning software from the XP machine,as there is Starforce protection on the game disc, but still no luck.
Any ideas?