Thanks so much for you guys who identifed iTunes as the root of this evil.
This issue was driving me insane. My laptop manufacturers helpdesk (Toshiba)
were suggesting a complete reinstall!

"vampchick21" wrote:

It was iTunes. For some very strange reason in Vista, when you install
iTunes it messes with the CD/DVD driver. Apparently there is no offical
version of iTunes for Vista just yet, although based on my reading of the
discussion forums for iTunes, Apple & Microsoft are working on it. I suppose
we iPod users will just have to approach the gates with our pitchforks and
torches to demand a version that isn't going to kill off our CD/DVD
driver....lol