I eventually found what the problem was on my PC. I built the PC myself and
used a motherboard from ASUS, with this motherboard came a cd with some
utility programs, drivers etc. and it was one of these programs called AI
suite that caused the problem, After I uninstalled it my DVD drive was able
to read and write as normal. This program basically gives you information
from your BIOS and allows you to fine tune settings from windows without
having to go out and enter the bios setup. I wasn't expecting this program to
cause the problem because from what I've read it's mostly DVD burning
programs that cause these problems. It could be some other program on your
computer that's causing the problem so the only way to find out is to start
uninstalling each of these programs and testing your dvd drive after each
uninstallation. Some programs to look at might be Realplayer, Nero, and I've
also heard that adobe programs caused problems with windows XP so might have
a similiar problem with vista.
sorry I can't pinpoint exactly what your problem might be but I think that
this should make things a little easier for you.