A little more information would be useful.
What kind of machine is this: Notebook or desktop, prebuilt or homebuilt? Was that dvd player ever seen, or did you just install it, or just build Win7?
What kind of drive is it, and does it have an SATA or IDE or USB interface? If you are familiar with the BIOS, does the BIOS detect it? Does it show up in Device Manager?
Some more detail would be most useful.