Windows RT 8.1: FAQ - Microsoft SupportWindows RT 8.1 is a Windows-based operating system that's optimized for thin and light PCs that have extended battery life and are designed for life on the go. Windows RT 8.1 only runs built-in apps or apps that you download from the Windows Store. Windows Update automatically keeps your PC up to date and Windows Defender provides up-to-date virus and malware protection. If you already have a PC o
