To get the Shift-Prt Scr or ALT-Prt Scr key working for copy-pasting window captures, follow the next steps:

1. Open the Registry Editor click on the Start button on your taskbar, then click on Run and type "regedit" and click on OK to start the regedit utility.
    
2. Expand HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\DirectDraw (see picture 1).
   
   

   Picture 1

3. Add or modify the DWORD "EnablePrintScreen" so it equals "1".
    
4. The modifications you made will be in effect after you reboot your PC.