hOW TO PUT IT INTO RECOVERY MODE?
By following this knowledge base article.
WILL I LOSE ALL MY CONTENTS IF DO THIS?
You won't lose your settings, calendar entries, contacts and stuff, but you will lose all your media. Why is that an issue? You have all your media in iTunes. Just sync it right back.
MOREOVER WHERE IS THIS IPSW FILE LOCATED IN APPLE WEBISTE. i COULDN;T GET ANY LINK .
Right click on this sentence and click ‘Save As…’. It's a 57.6MB file. Once it has downloaded, put your iPod into disk mode, connect it to iTunes, hold down the Alt key and hit the Restore button. It will ask you for the IPSW file. Navigate to the file and let it do its thing. Let me know if you run into any issues.
I'm glad to help but in future:
(a) Use Google. You could have easily found that knowledge base article yourself; and
(b) Stop shouting.