From Private Tier Software:
PrintScreen is the quickest and simplest way to capture a screen image and save it to your disk drive. Printscreen uses a the natural untapped code in all Windows to save whatever image that gets copied to the clipboard, to the disk drive. Including, the clip created when you hit the PRTSCR key on the keyboard. Press PRTSCR to save a copy of whatever you see on screen. It's simple enough, so its footprint is really small. Hardly no code needed and running in the background. It just watches the clipboard for images and save them when found. Works on any image copied to the clipboard, not just screenshots. There is also a good amount of other tools in the menu list, for those who may need them. My favorite is the Clean Text Clipboard, to take off all those Rich Text info when you just want to copy the text.