Annette recently updated to Windows 10, but now she has to boot up twice in order for the computer to completely boot up. Leo says there could be many reasons for a halted boot. External devices are the easiest things. Turn off Windows Fast Boot. It's a terrible feature that doesn't really speed up your computer. But what it implies is that your computer isn't warm enough when it boots up the first time, and so it stalls. This can happen with older computers. It can also be a sign of your hard drive failing. A new hard drive will solve it, and Leo recommends a solid-state drive (SSD). A failing power supply may also be a culprit.