Is there a way to reliably upgrade from Windows 8.1 to Windows 10? (I have time till tomorrow). I clicked on the windows icon in lower right corner, there selected Upgrade now. This caused the standard Windows Update window to open, where it gets stuck on Checking for updates... forever. Is it possible to download Windows 10 manually and just run it?
Yes, you can download the Windows 10 ISO from Microsoft. Once downloaded, mount the ISO and click setup as admin. Windows 10 will be installed on your machine. If you grab the ISO today, you can get the free Windows 10 ahead of the deadline. The ISO is simply a compressed installer of the operating system. You also have the option on that page to create a USB drive installer. Just click your pick.