I enjoy finishing some games with the Chess.com computer although it is sometimes frustrating to lose a game I won by resignation.  Since it isn`t possible (yet?) to get a computer analysis of Chess960 games I would like to ask whether a computer I finish my 960 games against plays Chess960 or standard chess, i.e. will it let me castle and will it castle itself if either 0-0 or 0-0-0 is the best move?

I know with Chessmaster, you can set up the board however you want, and you can declare whether or not castling is still legal.  I assume it is the same with most programs.

Chessmaster does not "play" 960 per se, but you could easily set up a match.

How do you set up the Chess.com computer? All I am able to do is to decide which side I`ll play and pick one of the 5 computer levels (plus some design stuff). To make it clear - when I finish a game here there is an option Finish Game vs. Computer next to the board.