Your computer is running slow. You've tried shutting down programs, opening the spreadsheet you're working on again and nothing seems to help. You call up the Help Desk and our first question is 'Have you rebooted?' This seems like a flippant response, but the truth is that rebooting your computer can solve many problems. Why don't we actually try to identify the issue rather than have you 'press a button?'
The answer to that lies in the way computers work. Keep in mind that this solution isn't limited to computers, but applies to all computerized devices such as cell phones, routers, iPads, smart televisions and more. Computers load their operating system into their memory. They also load all their various functions (such as 'Contacts' in the case of a cell phone) into memory as well. Usually the computer can handle these functions and your requests fairly well: the operating system keeps everything running smoothly. There are times, however, when a function or program gets 'stuck'. When this occurs, the operating system does it's best to 'unstick' the offending application. Sometimes it is not successful in this endeavor. The operating system itself can get 'stuck' trying to fix the problem. This tends to cause other functions to slow down and halt like traffic arriving to an accident on the freeway. Some other times programs simply leave parts of themselves behind when they finish like trash found on that same freeway. This requires traffic to slow down and swerve around the trash.
Starting your computer or device again cleans that mess out of memory and let's it begin with a clean slate. In essence what your doing is clearing the accident and/or trash from the highway and allowing traffic to proceed as it normally would. The reason we don't regularly troubleshoot this issue is that any program can cause it. We do investigate if you're needing to restart your computer or device frequently as modern equipment shouldn't require that.