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Explained: why a reboot is the go-to computer fix

Explained: why a reboot is the go-to computer fix

Explained: why a reboot is the go-to computer fix

It’s the most common answer to our computing woes: when your PC or mobile is playing up, try turning it off and on again.

In a computer, the only program physically built into the computer hardware is a tiny one, called the “bootloader”.  You may have heard of BIOS or UEFI.  When the computer starts up, this program gets control and loads, or “boots” another, much larger, program which serves as the “operating system” for the computer. We know these systems by such names as Unix, Mac OS, Android and Windows 10.

The operating system itself is made of up millions of seperate components which talk to each other, they have individual specific jobs – for example detect when something is plugged in to a USB port, that will then ask the USB driver to get its name, search for the new devices driver, install it, tell the operating system its installed, tell the user interface a new drive is available.  The user interface will add it to the ‘My Computer’ screen and ask the driver how much free space there is…..this continues on.

With this number of internal messages flying around, sometimes things can get out of sequence.

Starting from fresh

If the computer has many tasks to run – or a set of events occur in a sequence that the software wasn’t expecting – then tasks can get confused, either waiting for a message it missed or not realising it should have sent a message.

In addition, as tasks run, they fetch and use resources such as computer memory and, over time, the arrangement of these resources will become fragmented and harder to manage, just like it is difficult to find things in an untidy bedroom. A reboot may also be a temporary fix for problems caused by hardware that is becoming unreliable.

Modern operating systems are very adept at spotting and removing stuck processes and also work very hard to keep things tidy, but sometimes a computer can reach a state where the best thing to do is start again from scratch. A reboot removes every task and then restarts with a clean slate.


There are two flavours of reboot, which are often called “warm” and “cold”. You do a “cold” reboot by actually shutting down the computer  and switching it off then on again. A “warm” reboot, meanwhile, just reloads the operating system when you choose ‘Restart’. Sometimes a warm reboot will fix your problems, but if some of your hardware has got itself into a state where it is not responding to any signals from the outside world, you might need to use Shut Down or worse, power off your computer without choosing shutdown.

One thing reboots cannot fix, however, is malicious software such as viruses. These horrid bits of program usually insert themselves into the boot process so that they get control next time the computer starts up. The only way to get rid of these pesky intruders is to scan your system, find them, and remove them.

About The Author

Niki Odolphie

Niki Odolphie is the chief tech guru at Somerset Online Ltd who provide IT support for home and small business across Somerset and Wiltshire.

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