I have some picture files in NaN.jpg, but now it is not showing picture.
So how to retrive image of NaN.jpg files....

What exactly do you mean by "NaN.jpg"? I am unsure what you are asking.

i would imagine it is probubly a pic they downloaded or found on a computer, if it is one you yourself put on it, that you know is really a picture, try opening it with every image sofware you can lay your hands on, if you just downloaded it, it may be corrupt, try downloading it again, if you found it on your computer it could be

a.) a blank image
or
b.) not an image at all, there may have been a program that saves something, like config files, in that format

i want to block some website for my pc.
in my pc drivers/etc/host file is not there
but
divers/etc/iamhost file is available. i tried to
block some sites but it doesnot work.
so iamhost file how to use code to block
some sites.