Looks like a old or damaged disc. Burned discs don't have eternal life. Don't you have a backup?
Other things to try:
1. Another drive (or: try it with a friend)
2. Use the command prompt to copy. It tends to give more or better error messages.
3. isobuster from www.isobuster.com
I can't able to drag files from a data cd. There is no problems in other data cds which i have burned before longtime. This particular data cd has this problem, i can able to see the files but when i drag them to desktop or drive, they stop on the half way itself. Is there anyway that i can get those files to my pc ?