Cd/dvd drive not working & no where to be found

My hp pavilion dv4000 notebook's cd/dvd drive stopped working so I called hp to help me and spoke with them and they troubleshooted with me and took over my computer. He went through different steps and fixed the problem, but I can't remember what he did and my warranty is up. The cd/dvd drive worked when I was on the phone with him and then the next time I tried to use it , it didn't.

I put a cd or dvd in and it sounds like it is working and then it slows down and then stops.

So, I went into my computer and in device manager and the cd/dvd drive doesn't show up in either. So I went into registry edit because I remembered the hp guy going there and he deleted some things and made me reboot my computer. He said that this problem sometimes happens because of i-tunes and that I should download the newest version of i-tunes because it doesn't have that problem. So, basically I know very little about computers and hope that someone can understand my issue and help!

Also, I have windows xp if that helps with assisting me.

Fix CD Missing

Xp
http://www.dougknox.com/xp/scripts_desc/xp_cd_dvd_fix.htm

Vista:
http://support.microsoft.com/kb/929461/en-us

Once complete, please restart