GIVE ME THE MOST EFFECTIVE FREE DATA RECOVERY SOFTWARE FOR MY NTFS SYSTEM THAT DOES NOT REQUIRS ANY ACTIVATION FOR RECOVERY OF RECOVERED FILE. THANK YOU.

Personally I do not believe in free software as it will end up messing my computer with virus and spywares. So I look for cheap and good software. For recovery software, I bought one before, cost me a bit but working very well, and good thing is that it's one time payment and then it allows me to use forever. Take a look if you do not mind paying a bit to get back your files.
http://www.asoftech.com/adr/

There are many data recovery freeware out there that can work much more efficiently than some paid ones:
http://www.geeksdo.com/freeware/data-recovery.html

You can select one and restore all your wanted files back.

There is only one Free software "Recuva" for recovering deleted data, all other charges money. Try recuva first if it doesn't recover your data bcoz sometimes dere are situations when a particular software can't recover your data but other can recover your data intact in that case you can go for http://www.retrievedeletedfiles.net/

I like Recuva, for accidentally deleted files.
http://www.piriform.com/recuva