Windows Solitaire's random number generator is fun: start Windows Solitaire, press the F2 key and keep your finger on the key. What do you see? Yes, you will get a new deck only every second. What does this indicate? Most likely that Windows Solitaire's random number generator is initialized with the current time (with a granularity of 1 second) every time a new game is started.
Disclaimer: I am bored, because I finished my programming assignments for today, and I have absolutely nothing else to do (except for reading weblogs and playing Windows Solitaire).