You don't make a drive master or slave in the BIOS, you do it with jumpers on the back of the drive. If you do make the DVD drive the master you will have to make the current master drive on the same cable a slave, you can't have 2 masters on one IDE bus.

You obviously have no experience with this. It's easy enough to do, but I'm not advising you to do it. I have no idea of your capability.