I had the same problem. The embedded XP CD burning
software worked and then it stopped working and gave me
the error message to insert a writable CD. I went on
this group and got no workable answer. I think there is
an XP CD burning problem and Microsoft doesn't know how
to correct it and won't admit to it. I solved my problem
by loading Roxio Easy CD Creator (another CD writing
program) I did like the symplicity and user friendliness
of the original program but it did not stay.
If you haven't tried yet, you can try using system
restore to get back to a date when the program was
operational. I did this once, but the 2nd time I had no
restore points that would restore the original CD writing
capability.