According to Microsoft, all desktop, laptop and tablets that are running Windows 7 SP1 and Windows 8.1 are capable of upgrading to Windows 10. The following Q&A page should provide the answers to the questions you may have about doing so. The best way is to “Reserve a free upgrade for your existing Windows 7 or Windows 8.1 PC. The easiest way to get the free upgrade is to reserve, but you can upgrade even if you don’t reserve. Once Windows 10 is available, we’ll begin notifying devices that their free upgrade is available. Just open the Get Windows 10 app [in the Notification Area] to schedule your upgrade.”
Due to the many millions of computers that will be wanting to upgrade “Some notifications will go out as soon as Windows 10 is available; others may go out in the weeks or months following [its official release date].”
Windows 10 Q&A –
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9 reasons not to upgrade to Windows 10 — yet –