I recently crossed paths with a customer that was still using Windows XP and experiencing problems with a website. This led me to evaluate their options for continuing to use this once very common, but now unsupported operating system.
After 12 years, support for Windows XP ended April 8, 2014. Microsoft will no longer provide security updates or technical support.
https://www.microsoft.com/en-us/windowsforbusiness/end-of-xp-support
The most recent version of Internet Explorer in Windows XP was IE 8.0.6001.18702
Even Apple, Google and Mozilla Firefox have ceased to maintain browsers for this operating system, dropping support for Windows XP and Vista at the same time.
Chrome 49.0.2623.112
https://chrome.googleblog.com/2015/11/updates-to-chrome-platform-support.html
Firefox 52.9.0 ESR
https://support.mozilla.org/en-US/kb/end-support-windows-xp-and-vista
Safari 5.1.7
https://apple.stackexchange.com/questions/68836/where-can-i-download-safari-for-windows
An additional problem with use of IE8 on Windows XP is that it only supports up to TLS1.0 which is currently being replaced by TLS1.2 in many web applications.