You have tried pressing ALT+PrintScreen, right? It works in WinXP, i don't know how it works in Aero, i guess it doesn't work since there are all these programs for making it work ^^
this captures the entire screen
No, it doesn't. Print Screen on its own does that. Holding Alt copies an image of the currently active window...
Also with transparency support and free:http://code.google.com/p/zscreen/
zscreen have transparent corner and shadow effect.,and window background does't show my desktop,If you wanna turn off transparent corner and shadow effect,and let people know your desktop,just turn on in option menu.