My cd rom and dvd rom are gone

My cd and dvd drives are gone! I have win. XP and they worked one day and now they are gone. I tried to delete the drivers and restart my computer but they're not in the system devices. I tried this too In Regedit, go to HKEY_LOCAL_MACHINE; open SYSTEM open CurrentControlSet open Control open Class click 4D36E965-E325-11CE-BFC1-08002BE10318 on right side, click LowerFilters and delete on right side, click UpperFilters and delete no good! The UpperFilters and lowerfilters are not there. What happened and how can I fix it? Terri

I had this problem, if you unistalled iTunes inproperly then they are probably gone. Try reinstalling iTunes and see what happens.