You might often see messages or other references to ‘Windows Update’. The Windows Operating system is a very complex software program, consisting of probably millions of lines of code, and the developers don’t always get it perfect first time! When they find some issues to be resolved, it may be security issues, usability issues or something else, the developers issue a Fix to correct the problem(s). In order for all PCs to get this Fix as soon as possible, the Developers transfer a file to your PC at regular intervals, that contains one or more fixes, or Updates, to the Operating System.
The default process for receiving updates is that your PC will ask the system if there are any updates to be processed, usually when the PC is not doing anything else at the time. If there are updates to be downloaded, the PC will automatically do this for you, and you may get a message to say that ‘Updates are available’, or the PC may install them automatically at a fixed time during the day or night.

Other software suppliers also have a similar system to keep their software up to date, so watch outr for any messages that are associated with Updates, and make sure they are installed as soon as possible.