You installed a brand new DVD drive, or hard drive and the thing didn’t work. You returned it and got another one, it didn’t work either. What is going on here? It very likely could be the master slave setting. You see computers aren’t that smart they can’t even tell which drive should go first in line. If you have a SATA system it doesn’t matter for you because each port has a priority built right in, but for all you who still have IDE systems check the drive for master slave settings. There should be a map of them on the back of the drive. If it is the only drive of it’s type ( such as the only DVD drive ) then it should be set to master. If there is another one then it needs to be set to slave. This should make the drive work properly with no more need for returns.