Even though Microsoft is withdrawing further support for Windows XP, they are still going to continue to allow anyone (and as of right now, this is fully 27.7% of the PCs out there) who still runs XP to download and install every single windows security, performance, and driver update they've ever issued. They will just not be building or issuing any new XP updates, so keeping your XP OS safely secured and stable will take just a bit of extra effort and initiative on your part. Here are some really good, useful techniques and tips for keeping your XP box up and running well and securely.
Keep Your XP Alive, Well, & Running for Longer

Here are a whole bunch of very good useful tips to get your computer back up to its peak 
performance with a good, thorough (inside & out) Spring Cleaning.  Definitely some very good advice.

Windows XP - It's been running, and running fairly well, for over a decade, but, as with most good things, it is finally coming to an end (together with Microsoft's Office 2003 suite).  What are your options?   Here's a good resource to see whether you (and your computer) are good candidates for upgrading to Windows 7, Windows 8, or a range of other possible solutions).  http://www.howtogeek.com/172243/windows-xp-users-here-are-your-upgrade-options/