Be sure you guys update your Windows XP machines and encourage your families and friends to do so as well. You'll want to upgrade to windows 7 or better before April 8th (yes they could upgrade to vista but that would be a bad idea when windows 7 is so much better). Windows XP is losing support on April 8th and that means a few things:
1.) NO more security updates from Microsoft which means these machines will become more open to malware and nobody will be there to correct the loopholes and nobody will be able to support or help you if you do happen across some malware.
2.) NO more new downloads for microsoft security essentials on Windows XP. If you have it you got it but if you don't then you won't be able to get it for Windows XP any more from Microsoft’s site. Third party download sites might have it but it is unclear if they will activate properly or if they are even safe to use.
3.) Support for Microsoft security essentials on Windows XP will end a few months later. No more updates for new malware so you if you catch something new you'll have a hard time to dislodge it.
4.) Software will slowly over time become less compatible with Windows XP and some programs while they may get updates from their vendors may start to get buggy or unusable after a year or two. You know like your video card drivers or your antivirus programs.
Microsoft has a nice little tool to help with determining if your machine could be upgraded to Windows 8.1 which is linked to in the article. It also links to instructions on how to upgrade a machine with pictures to help novices through the process.
The alternate route is instead of upgrading to a newer version of Windows or buying a new machine you can try and install a flavor of Linux to keep the machine going for awhile longer assuming they are very adventurous or desperate.
If you guys want a good long term heads up on the lifecycle of windows this is a great resource.
Remember folks, computer security is the responsibility of the person behind the keyboard.