The three-at-a-time version is frequently unbeatable. However, there's an option in the settings to let you flip through the deck one-at-a-time, which makes it always beatable.
Klondike Solitaire, or at least Microsoft's implementation of it, is fatally flawed. A shame, it can be fun sometimes.
I can't argue with that, was just giving some feedback in case you wanted to look into it. Oddly enough, it froze around the time I tried launching IE 3.0 :)
Either way, really impressive software, very well executed.
Edit: happened on Chrome too, froze the tab but not the app.
JS Console: