DVD drive help

got my new dvd drive but,,,,,
it reads CD's DVD's with out a problem but when i put a blank DVD into the drive,
the drive icon in MY COMPUTER changes from a DVD-Ram Drive to a CD Drive and the blank disc shows as having 0 bytes capacity.

ive had a look around on google looks like theres quite a few peeps with this problem but couldnt find a solution.

anyone had this problem or got an idea of what the fooks goin on?

from what ive read it isnt a fimware issue ,
i got that sony dual layer one.

its on a seperate IDE from my HDD's, but its ont the same as my cd-rw both are set master and slave acording to there possition on the ribbon.
ive tried with out the cd-rw connected and from a fresh install but still the same.
this happens with my old dvd-rw aswell same make different model.