<< 
except you dont need the ctrl button.
alt+printscreen copies just the current window.
 >>
ok so what's your point?  That just copies your current window.  Since this is a desktop thread i'm "assuming"  he wants to copy is whole desktop. Hence ctrl + printscreen.  
Can somebody tell me if i'm wrong about this copy desktop thing?  That's how i've always done it.
 
peace
sean