Windows normally receives automatic software updates from Microsoft. Most of these updates are for security problems that could be exploited by malware or hackers. Microsoft normally releases software updates to fix these vulnerabilities as they discover them. It is very important to allow these updates to install.
Microsoft support for Windows XP ceased in April 2014. Microsoft support for Windows Vista ceased in April 2017. Windows XP & Vista will still continue to work but will no longer release Microsoft software updates. Any security problems discovered in Windows XP/Vista after this date will never be fixed, which will leave them increasingly vulnerable to cyber attack. Also software support for many other third party programs may also not be available.
To maintain the best possible security, you need to be running a modern version of Microsoft Windows that is still supported and updated. The current version is Windows 10.
This can be acheived in two ways:-