A reader had a question about the term “clean install.” She wrote: “What do you mean by a clean upgrade from Windows 7 to Windows 10. I had Vista on my computer when I bought it. Microsoft mailed Windows 7 to me to install. Does this make a difference? One day a note popped up on my computer on right lower corner that, stated my computer was not compatible for Windows 10, it keeps offering an upgrade on my computer to upgrade to Windows 10 now.”
I believe the term you want is “clean install.” A clean install means that you are completely overwriting all of the files and programs on a PC with the new operating system.
Users of Windows 7, 8, and 8.1 have the option to do a free upgrade to Windows 10. This upgrade will leave your folders, programs and settings intact, but upgrade your OS to Windows 10 and install some new apps only found in Windows 10.
If you upgraded you PC from Vista to Windows 7, you should be eligible for the upgrade. I’m wondering if there’s a typo in your question. Did a note pop up saying your PC was “not” eligible for upgrade or that it is “now” eligible for upgrade? If it says “now”, then you should be able to upgrade. If it says “not” eligible, there may be some type of hardware issue.