After a google I found the solution.We need to uninstall and install the dvd drive from device manager.Links are given below.
http://forums.whirlpool.net.au/forum-replies-archive.cfm/729655.html
http://www.vistax64.com/general-discussion/157820-help-please-dvd-rw-thinks-every-disc-needs-formatted.html
Hats off vista...