What i did to "has stoped working"

[Rak3]

i Played it again and copyed the serial than i located ubisoft launcher it was in my Program File > Ubisoft folder > Ubisoft Game Launcher (folder), I Ran UbisoftGameLauncher as Admin, and logged in to UPlay, than added the serial number, clicked play it brought me back to steam and clicked play on steam and it worked for me :Y
Don't know if this would help anyone else but GL
btw im using vista ^^