This is perfect Answer i got from syed shanu.
Hi,Create a Winform project,
1)Add Timer Control to it.
2)In timer Tick event check current time== your preferred time for example
if(currentTime=="18:00:00")
{
doBackup;
}
3) In form Load enable the Timer.
4) Always run your program in server.
You can also use SQL Job have a look at this no need to create separate program for this. http://blogs.msdn.com/b/sqlagent/archive/2010/10/12/create-a-database-backup-job-using-sql-server-management-studio.aspx