Delete the files in the CD Burning folder.
<quote>
Delete CD recorder temporary files
To delete files and folders from the CD recorder temporary storage area:
1. Double-click My Computer, and then double-click the CD recording drive.
Windows displays a temporary storage area where files are held before they
are copied to the CD. Files or folders located in the temporary storage area
are listed under Files Ready to Be Written to the CD.
2. Under CD Writing Tasks, click Delete temporary files.
Windows deletes the files and folders from the temporary storage area and
moves them to the Recycle Bin. NOTE: When you delete the contents of the
temporary storage area, you make this area available for another set of
files and folders that you want to copy to the CD. The files are not deleted
from their original location on your computer or from the CD.
<quote>
from...
How to copy information to a CD in Windows XP
http://support.microsoft.com/kb/306524
Music files are not cleared from the temporary storage area after you copy
music to a CD in Windows XP
http://support.microsoft.com/kb/890735
%userprofile%\Local Settings\Application Data\Microsoft\CD Burning
or
C:\Documents and Settings\Your Name Here\Local Settings\Application
Data\Microsoft\CD Burning