Use "any", "anything", "anybody", "anywhere" for questions:

Are there any films on the hard disc?
Do you have anything in your pocket?
Did you speak to anybody?

Use "any", "anything", "anybody", "anywhere" for negatives:

There aren't any ostriches in Australia.
I dont know anybody here!
Paul couldn't find his laptop anywhere.

Use "some","something", "somebody", "somewhere" for affirmatives:

We saw some bison in Texas.
I must take something for this cold.
The plane left an hour ago. It's somewhere over the Atlantic now.