OS: Windows XP SP2

I've just changed my original dvd drive for a dvd rw drive. It's dual drive, the other is cd rw and before installing both the drives were working. After changing the dvd drive to a rw drive, now the cdrw drive can't be found. It isn't displayed in device manager, though the new drive is. Also in properties for the drive it says it's in location 1 of 1, any idea why it no longer recognises the second drive?

Any help much appreciated.
Thanks
Michael.

EDIT FURTHER DETAILS:
Always post only some of the details, heres the rest
The drive has power going to it, opens, you hear it spining the cd, the light flashes, I plug in my memory stick and it gives it drive letter F, the letter e is not assigned though this is what the slave in the dual disks used to be. Trying to access it in dos gives a cannot find the drive specified error.

Any ideas?

One thing isn't clear to me. Did you change the jumper on the back of the new drive to match the one it was replacing?

I removed the connection labelled master for the disk drive I was removing, and attached it to the new drive. The sockets in the back of the new dvdrw drive matched those of the previous drive so I simply unplugged one and plugged the connections into the new one. I'm sure this is done correctly as the new drive works fine, though the second drive isn't recognised.

Cheers for any help
Michael.

The confusion grows...

I opened the case to find that the master connection was still plugged in, though the slave had come loose, that's why the second cd drive wasn't being recognised. Though when I plug this in, only the slave drive is working, and the master drive has same functionality as the old one, in that it lights, opens etc, though isn't visible in the device manager.

I put the old drive back in, and both work fine. Is it possible the new drive just isn't capable of working in a dual cd drive or is that crazy? The only reason I ask is it's called a DVD Dual 16x Double Layer drive, and it works when plugged in on it's own with the IDE cable, but attach a slave or even make it slave and other drive as master and it just isn't recognised.

Any help much appreciated.