I use a program called MW Sanp.
It's really good.
It can reconize a certain area/window, a single square, any size, and a full desktop.
You can also save the pcture as many different file types.
I have the same problem that you do with print screen.
Heres a link to the download (it's free!):
http://www.mirekw.com/winfreeware/mwsnap.html