As we all know Windows XP is outdated and now unsupported by Microsoft. Came across a couple of operating systems that might be useful for you to revive an older and slower computer. It is not Windows and will not run your Windows software. If you still have games and other things you really like and they still work on your XP machine, just don't go on the Internet with it. Keep using it for as long as the hardware continues to work.
Check out these two:
Linux Lite and Zorin Lite. They are both Linux OS and look a lot, by design, like Windows XP. They come with all you need to surf the net, even Facebook and email, and do word processing, view YouTube and other videos. And work with pictures.
To try them out you download the ISO file and in Windows 7 or 8, right-click the downloaded file and choose burn to CD/DVD. Put a blank DVD for Zorin or a blank CD-R in your drive and a bootable CD/DVD will be created.
To try it out, boot from the CD/DVD and you will run a live version without touching your hard drive. From there you can choose to install it on your hard drive either as a second OS leaving XP as it is or wiping out XP and installing the new OS. The later option will REMOVE ALL YOUR FILES so be careful if you have stuff you need.
You will be surprised at how fast each of them run on your old, slow PC. Oh, you do not need any anti-virus or malware checking software with Linux.