Just a FYI but on Vista/Window 7 there is no need to use the print screen open paint carry on, if you go to start>accessories and choose Snipping Tool it will let you take a screen grab more easily

And for quickness just right click on the snipping tool icon in accessories, choose properties, shortcut tab and where it says shortcut keys put in a shortcut. I have my shortcut as holding down ctrl,alt and the S key