Changing windows xp into windows 7

Make sure your system can support running windows 7.

Use Os.click to download the version you want on a separate computer, and then use BalenaEtcher or Rufus to flash the ISO image onto a USB drive/DVD/CD.

Then boot into the bios on your windows XP PC. Make sure that you can boot from a USB drive or whatever medium you chose, then power off the computer, insert your installation media. While the computer is booting, press the multi boot key (usually F12 on most computers) and select your medium. Follow the onscreen instructions, and you should be good!