I downloaded Winboard. It seems to work fine.

But someone also mentioned Crafty. What is the difference in them?

And is there any way I can set the computer opponent in either of these programs to be a bit on my level (that is, beginner)?  I think it woud boost my morale if I could win once in a while.  :)

stwils

Winboard is a board (an interface with which to play chess)

Crafty is a free open source chess engine that can be used as "the brain" of Winboard.

http://www.cis.uab.edu/info/faculty/hyatt/hyatt.html

http://www.tim-mann.org/xboard.html

I believe that the current version of Crafty (v22.1) has a level command so that you can "nerf" its playing strength. More details may be found on the Crafty Chess site.