Blu-Ray drive not reading blu-ray disks

I have recently had my mother board and Ageia PhysX card changed by Dell to try and get the PhysX card recognised as being fitted. This still didn't work so I re-installed vista and strangely my PhysX card was now recognised as being fitted. Now though my blu-ray drive has stopped being able to read blu-ray movies. It worked perfectly before I re-installed vista but the drive doesn't even see a blu-ray disk as in the drive with explorer. Normal DVD movies play ok and the drive can read data disks, it just can't see blu-ray movie disks.

Can any of you wizards shine any light as to why this has happened.

My drive is a Sony Optiarc BC-5500A fitted to a XPS M1730 Laptop.