This is an amazing opening trainer. It took me around an hour to work out how to use it but now I am hooked. The support is also excellent!
There is a good chance it wont work straight away on Vista or Windows 7.
You may have to download a microsoft file see technical help
http://www.chesspositiontrainer.com/English/Downloads/FreeChessSoftware.aspx
and you may have to make some small adjustments
http://community.chesspositiontrainer.com/forums/2/460/ShowThread.aspx#460
But beleive me this is well worth the effort.
(There is also version 4 available but since its undergoing Beta testing I haven't tried it out yet!)