Follow this steps to make a print screen:

1. Maximize the window you would like to capture.
2. To copy/capture the current window, hold down ALT + Print Scrn at the same time. To capture the entire screen, just press Print Scrn.
3. Open a new document in MS Word, MS Photo Editor, or Adobe PhotoShop or Paint
4. Paste the screen shot by holding down CTRL and V key at the same time.

If you don't know what is the Print Scrn key go here to see a picture.