Sony DW-D22A Won't read DVD's

Hey,

I’m a bit new to DVD-Burning and renetly bought a new SONT DW-D22A.
for the last few weeks i’ve ben using the drive to READ and WRITE CD’s only and i had no problem. win xp show i have 2 cd’s drives, 1 is the dvd rw and one spouse to be a regular cd drive (even i have only the sony dw-d22a installed).

my problem is this drive WONT READ ANY COMMERICAL DVD MEDIA… it wont recornize any orginal dvd what so ever. i tried every program possible , i also try to upgrade the firmware to bys3 and even to the latest firmware of the Sony.710A.BYX4.stock . but nothing else - everything looks fine - windows recornize the drive fine - but it just wont read any real dvd!
im also have nero 6.6.0.16 installed and when i insert a blank dvd media - it recornzie it and i can burn to it, but when any commerical dvd video is inseret - its like no disc is in the drive, not for nero, not for nero, not for dvd shring, not for media player 10 - just like no dvd in the drive. im really hopeless

please help!