Computer Study

I'm wondering what other players are using as an aid to study. I have Chessmaster 7000 but it keeps crashing on my new PC. My mac has a good program but I can't set up positions and replay vaiations. I trying to set up and study different openings. Using a physical board amd pieces is time consuming. really not looking to spend any money right now. Any suggestions would be aprreciated. Thanks.

I have Glaurung 2.2 for my mac, it's a pretty strong program. 

http://www.glaurungchess.com/

Good stuff can be found here:

http://www.chess.com/downloads/playing+programs+engines

Right now I'm using a combination of Majestic Chess, Winboard with Rybka, and several different internet sites. I fully intend to buy another program or two but haven't gotten around to it.

I use Shredder Chess with Rybka 3.0 engine, but neither are free if that's what you're looking for. Rybka is the strongest engine in the world (not my opinion) and Shredder is really good for blitz and chess960.

I like Arena, It is free and very complete. You can use many free engines with it (including the free version of Rybka). There are also different opening books you can download on the Arena site.

Alright. That's a start. Thanks.