you can only delete file on a dvd-r or +r if the disc is in UDF mode. then it doesn't truly delete it. it hides it and make you think that it is deleted.
Now you can delete a file on a dvd-rw or +rw
The Ultimate Hard Drive Utility PowerMax 4.23. (It now has the ability to clean a Boot Sector virus on the quick erase option.)
The best browser Netscape 8
Have you accidently delete something? Look here (trial. the better one) and here(free)