Houdini 1.5 is excellent and free. You also need a GUI (graphic user interface). I've heard Stockfish is a great engine too. 2 popular GUI's are Arena and Scid v. PC. All can be downloaded from chess.com right here:
http://www.chess.com/downloads
I use an older version of Fritz (cheap) loaded up with Houdin 1.5a and HIARCS ($50) so I can't say anything from personal experience about what's the best free stuff but try a "search forums" and you'll find lots of previous threads. Have fun!
Hi everyone,
I need a chess engine I can run to evaluate my games and improve my gameplay. I can't afford Houdini so what other options are there that are free with a high analysis strength?