Hp pavillion a810N xp.. Can't burn a CD?

Question

hi-
I can no longer burn CD'son my computer. If I put a Music CD in the CD reader- it plays. If I put a DVD in it reads it and plays it- no problem. When I try to burn a CD it says drive cannot be found- or no disc in drive (even if there is one in it). I downloaded nero and had no problem burning a CD... this is just a trial version- so not a long term fix. Can anyone help me figure out how to get the original HP CD burning software back on my computer or if it somehow got turned off... how to urn it back on?

Thanks for the help