Recently I was working on net, and suddenly a error message occurred that eventually lead to the not responding of the browser and my other applications and my laptop shut down on its own. When I restarted laptop it is showing no bootable device found and when I put in operating system disk it is not showing internal hard disk of the laptop or any disk partition of the hard disk. Please help me I have my business in the soup because of this blunder.

The symptoms that you have provided indicate that your hard drive has died. You could try removing the hard drive and re-inserting it to see if it's just a poor connection problem. Hard drive checking tools should be provided by the manufacturer on their web site.