i found some kind of bug:
I had installed Sam and Max into the wrong directory.
i wanted D:\Games\Sam and Max Season Two\
but i choose D:\Games\
No Problem i think: So i deinstalled the Game but after 15 Minutes Deinstalling i take note that he is deleting Left 4 Dead so i thought: "WTF??!?!?!?!?!?!"
as i see the deinstaller only delete the directory (i didn't know that Sam and Max haven't any Regesty entry. Thats why i used the deinstaller)
So i lost over 100 Gigabytes of Games (Miiror's Edge, Steam with over 20 Games, World of Warcraft Cataclysm Beta and many more).
So i'm now hardy pissed off and i hope Season two is great than Season one.
Thanks telltale for this GREAT end of my Birthday..