Keys don't respond
If a key press does nothing, it is probably because the wrong window has the focus. As you know, Windows is designed to let users open up a number of programs at once on the same screen, so each window will respond to different key-press combinations. You can see which window has the focus because its caption is coloured differently from all the others. The solution is to click anywhere within the window which you want to use, then press the key you wanted.