Microsoft may be gung-ho about upgrading your PC to Windows 10, but some of the company's partners aren't quite as enthusiastic about the new OS, at least if you ask their tech-support reps. While going undercover for our annual Tech Support Showdown — in which we test each laptop vendor's phone, social and Web support — we spoke with several agents who either actively discouraged us from upgrading to Windows 10 or failed to understand core features of the new OS. Phone-support reps from Dell and HP told us they discourage users from upgrading to Windows 10. An HP rep even tried to help us roll back to Windows 8.1 during one of our support calls. A Lenovo rep had nothing negative to say about Windows 10, but was confused about how Cortana works.