dude dont u have the dell manual???? my manual explains everything really well....u could check out manuals online at dell's website. my dell dimension uses cable select which means that a single cable has 2 connectors-1 4 primary hdd and 1 4 secondary hdd so depending on which connector is connected, an hdd will b automatically assigned primary or secondary. i dont think that u can turn the slave on without first connecting a hard drive. and i think that a cd-rom drive uses a different type of cable...not sure wait 4 others 2 reply...
EDIT: check here 4 ur manual if u dont have it:
http://support.dell.com/support/edoc...s/sm/index.htm