Thank you for your reply
I did delete the file but when i insert another DVD it appears again. It looks (to me) as a suspecious virus.
Another thing i forgot to mention about the data loss in my DVD i discussed earlier may be the shortage of space on my drive from which i was transferring data to DVD. Widows warned me about running out of disk space but i ignored and continued to burn data on DVD. I think that may be the problem i lost data after burning.