I've spent most of the weekend rebuilding my desktop PC; as part of this, I've spent an inordinate amount of time watching installer progress bars. So I've been playing a load of Solitaire while waiting.

I think there's a bug in Windows 7 Solitaire, because I've only one 1 out of ~40 games played so far.

What are the expected odds?

I just did a bit of a test... 2 out of 4. Not a large sample by any means though.

You're at the mercy of the RNG in Windows Solitaire for whether a particular game is winnable. Last time I checked, you couldn't see/input the RNG seed that is used unlike the FreeCell so it would be more difficult to test.

For the Windows rules, Wikipedia claims that 82-91.5% of Klondike Solitaire games are solvable. This probably checks all possible moves from an initial position (i.e. that you backtrack if you get stuck). I was wondering what the odds are for a naive strategy (i.e. me), because I can rarely be bothered to backtrack.

On the other hand, Windows Solitaire probably doesn't use the CryptoAPI RNG, so you might be right there...