What To Do When Kindle Does Not Connect?

IN the morning over the weekend my kindle would not connect, also my husband  could not get a good signal on his blackbery either.  Also, my batter was about half full, so I then charged it and tried in the afternoon.,it then seemed fine.. I know about turning off the wireless but at first forgot to turn it off.  Does the kindle always have some sort of a screen picture on it?  It did not have anything on it, when I went to turn it on. Itried turning on the settings and still it did not work.