Linux Mint 17 “Qiana” KDE Edition is now available to try. It’s still a development release so it’s not wise to install it on production machines just yet. Based on Ubuntu 14.04, it will receive security updates until 2019.
Windows XP has reached the end of life and pretty soon it won’t be supported anymore by Microsoft. This means that there won’t be any updates released you you’ll be left with vulnerable software. If your computer runs Windows XP just fine but it may not be capable of running Windows 7 and you don’t want to upgrade your hardware, maybe it’s time to think about moving on to Linux.