i have sony dvd rw dw-g120A (id:1 HA:1) and write software nero 7 ultra, my system configuration XP profession now I explain my problem,
1) When I insert CD automatically popup CD information and I notices my computer there I seen all the details of CD (space and any information in that Cd) I can write and read operation all normally working ok.

But when I insert DVD (blank or writeable ) I can’t notices any data details in my computer i can’t access dvd drive. Plz help me who can I rectified this problem can I change dvd drive or any software problem. I need your valuable replays

Have you checked in device manager to see if it detects the DVD drive correctly? You could try reinstalling the current drivers or if there is any newer updates try installing them.
If the driver option doesn't work possibly go to system restore and go back to when it was working if possbile