print screen does not work

If I am going through the process of trying to print screen but nothing happens, although I know the key stroke is getting to the computer. I have got a logitech usb keyboard but the computer shows it as a standard microsoft thing? Any ideas? Thanks.

To capture a screen shot of the entire screen to the clipboard, press the PrintScrn key.

To capture a screen shot of the active window or dialog box (for example, the WordPad application window or the File Open dialog box), press ALT+PRINTSCRN.

The SHIFT and the CTRL keys do not affect the full screen capture.

For more information visit this kb article - http://support.microsoft.com/kb/173884

When you press the PrtScn key on the keyboard then it copies the entire display and also the desktop wallpaper to the clipboard. If you press the Alt+PrtScn key then it will copy only the active Window to the clipboard. And then to view it, just open paint and then press ctrl+v and it will get pasted. Then save the image to the desktop.

here is the simple soln: press function (fn) and print screen (prt sc) keys together n enjoy.