So rebooting your computer...it can and does fix many issues. That said, the title of this tip also can apply to specific devices attached to your computer such as printers and scanners and also works with your classroom/office phone! 

Examples:

• Your phone receives phone calls but many or all buttons do nothing. There's a good chance, unplugging the main cable and plugging it back in (turning it off and on again) will fix it. If not, maybe you have a stuck key...
• Can't print? Already rebooted your computer? Try turning off the printer and turning it back on!! 
• Computer just acting funny, slow or unresponsive? Have you tried turning it off and on again? ;-p

Why does it work? In a nutshell, there is certain code executed by the computer or device on startup..when you turn the device off, everything that was running stops and the code that is executed at startup starts fresh. Many times, whatever is causing the problem is forced to go away.