HP PC and DVD/ROM problems

[MouskyMan]

i have a hp pavilion 7925 pc.i hooked up a dvd rom to it and it aint finding it,i checked the bios,its not in there either,but when i put a cd/rom on it,it recognises it.i cleared the bios etc,still doesnt work.i also need to boot windows,well my windows xp cd.the harddrive is empty and needs windows xp re-installed on it but i cant boot the cd.how can i fix this problem? and is there any other way of booting windows cd to do a format without a cd? like with an ipod or from the actual harddrive it selfself? the other cd/rom which is recognised doesnt work,it keeps on ejecting.

 

[Tmagic650]

How is the DVD drive set? Master, Slave, CS or is it SATA?