CD-ROM drive not recognized

I have a Sony VAIO laptop- VGN FJ 170.
Anyways, For some reason, the CD ROM isn't being recognized. I looked in my computer and it doesn't even show up. I haven't changed anything- at all and even a few weeks ago I used a Interactive CD that came from one of my text books. I did leave it in, but I don't know if that would do anything to it. Also, it has a hard time recognizing external hard drives when several months ago it had no problem with that at all.

When I put a CD in, i heard the machine working to recognize it and the CD spins but then it just stops later and nothing happens.

Thanks in Advance :)