A very common query!

Hey guys, here's a very common question I came across again today! Since I had written a reply, I decided to write it here too :) So here it goes..

QUESTION: What happens when you delete a file from your computer?

ANSWER:
Every file on your computer has an address, which is not comprehendable by us. Windows keeps an "index" of all the files on the hard drive with their address. Its eaiser for it to access any file this way, specially when HD capacities are going to insane levels. So when we delete a file, the address of that file is deleted from that index, or any reference to that file is deleted, making the file unaccessible. The file is actually present there. Now when the OS needs more space for itself to work, it starts using space and when it comes to such address which is not accessible, it simply uses that place to keep some other file, erasing the previous file. When you quik format, simply the "index" is deleted. When you full format, the head of the HD goes to every address and removes the file completely.
Data recovery softwares don't recover the files by the "index". They go to each and every sector of the HD and see if the file is not overwritten, and recover it.

I hope it helped in some way! ;)