Revert to previous version of Windows
I posted yesterday about an error message on Windows 7. Turns out my mom was given a pirated version of Windows 7. The guy who installed it was a friend of my sister's. I need to know how to revert back to the Windows version (XP) that came with the computer. All the help articles I can find on Microsoft say you need the installation CD for Windows 7. We don't have that since the guy installed it for mom himself and never gave her anything. Thanks for the help!