Insert the disc you previously created and run setup.exe.
Accept the license terms and the installer will download the latest updates.
Then, the installer will auto-check if your system meets the minimum requirements. If it does, it will show a ‘Ready to install’ screen. It may also display a ‘What needs your attention’ window, explaining any reason why Windows 8.1/8 can’t be installed and what you can do about it.
Click Install and your PC will reboot. You’ll see a Windows logo, followed by a language selection menu. The process should work automatically.
Finally, Windows 8.1/8 will boot, ask you a few questions, and then ask you to sign in with your Microsoft ID.
It is necessary to mention that even if you successfully upgrade from Windows XP to Windows 8.1/8, it may not run smoothly, since the PC running Windows XP will be an older machine, having been running quite a number of years already.