IN ONE CLICK... http://www.prntscrn.net/download/PrntScrn.NET/ Its free and useful check it out i know you will like it.
with normal print screen, you need to press print screen then paste it... wif this program it print screen and saves, i guess its good for making tuts or something, since alt tab to paste is annoying sometimes =.=
for a start you can only capture one image with the print screen, you overwrite the previous image if you print screen again. it is not completely useless but it aint far off.