i have been asking questions and getting answers for a long time here on Computer Hope.. so i'm going to try be useful for once. this is something i always do when i can't close a program. (always fixed crashes on World of Warcraft.. and has helped other times in the past too when i can find no other way of closing)
Windows Logo Key+Rtype "cmd" (type slowly)
press Enterwait a few secconds...
Alt+Enterwait for command promt to display (black screen)
Alt+Enter again
your task bar will now show.
right click the program on the task bar and
Close.
hope this helps someone