Most playing programs have that feature. Just paste the FEN string into WinBoard, Arena, Fritz, etc.
Software?
Thaks for answer.I am quite new player,can you please write how can i do that.Sorry,but i dont even know,what is FEN string.
Thanks you for your trouble.

On most (I think 'all') games played on chess.com, you can find a FEN string at the right hand side bottom of screen. You could use that.

In addition to pasting the FEN, you should be able to edit the position manually. Look for a command to "edit position" or something similar. Then you will be able to move pieces on the board or start with an empty board and add pieces. When you are done, you can play against the computer from that position. Any commercial chess program supports this, and most free ones too. Get one and read the documentation or explore the interface to find the particulars for whatever program you have.

I find that the Chessbase products are top-notch. ChessbaseLight is a free, very Fritz-like program that has a ton of options. You can get it here:
http://www.chessbase.com/download/cblight2007/index.asp
Hello to all chess fans.
I want to know,if there is any software or program,where you can insert position on the board,and than play agains computer from that position on.
Thanks for any answers.