Computers running Windows 7 and Windows 8.1, were not designed for Windows 10 but are eligible for the upgrade. Seeing as its not officially released yet your not going to see very many, if any PC's with a Designed for Windows 10 sticker on them. The "not designed for Windows 10" comment was likely because there were no Windows 10 drivers for your device from the manufacturer. They are basically telling you, you're on your own if you upgrade, don't call us if you have issues. My desktop PC's aren't even designed for Windows 8 let alone Windows 10 and they can run 10.