Setting the jumpers on a DVD ROM

Your vague post is not very helpful, and the model number of the drive yields no results.

Assuming that this is an E-IDE optical drive (connects with a thin wide ribbon cable), set the jumper to master if you are only connecting one drive to the system, with the drive being connected to the very end of the IDE cable. If you are connecting two drives to the same IDE channel, set the drive at the very end of the cable to master and the drive that will be connected in the middle of the cable to slave. You can also try setting both drives to cable select, which will automatically configure as master or slave based on where the drives are connected on the IDE cable, though I've had problems with cable select in the past. Enter the system BIOS and make sure that auto or auto detect (under the drives category) is selected for each location that a drive is connected to.