Hello...need some help

Got a sony DVD rw for my dell dimension 8400(xp) last week

It already has a CD/DVD combo and this works fine.

When i put the rw in the hardware is detected...the plug and play option comes up and installs the driver...although the device is not detected in my computer...It then prompts to restart...which i do....

Then when windows boots up the same thing happens as if it hasnt been installed...

i just cant get it too work....

could it be that it wont work in a dell system.?

does it have to be a dell part???

any help would be much appreciated