How does Windows 7 handle leaving programs open when you log out and opening them again when you log back in?

There was a user at work whom was conceed that someone had broken into his/her computer because windows were opened on her desktop upon her arrival.

However; what really happened was that windows updates had been applied to his/her machine, and he/she apparently didn't log out before hand (even though he/she thought they did).

The user was ruing Office 2010; I've noticed that on my own machine when this happens Office does not re-open the documents that were open initially most times, but it will open the same number of windows that you had open upon logging off. It seems to be some sort of an attempt at making Windows 7 do what OSX does in this situation; and I can't tell if there is some sort of issue with our setup here, or if this is some sort of security feature.

So I guess my question is; in detail, how does Windows 7 handle the re-opening of programs that were open upon log out when booting up again?