I had installed sp3 by replacing sp2 in c drive.it worked.after 2 days it started creating problem and windows could not start properly.when I again put the cd for installing sp3 it was saying could not install catalogs.so ihave to format my c drive.I had some data which was lost.can I get it back??

SP3 for what system as your question is unclear.
The more information you give the better we can help.

Which program are you talking about?