Matthew gave his mother in law a Dell computer Inspiron 17R 571 running Windows 10, but it's taking 5 minutes to boot up. Leo suspects that the spinning hard drive may be starting to fail, with difficult to read sectors. It could also be software that's hanging up the bootup process. Matthew should try using the boot log to see what may be causing the issue. He can get to this by holding the Shift key while its booting, and he can choose to create a boot log on the root level of the drive named bootlog.txt. Leo recommends getting a new hard drive, and while he's at it, he should go with a solid state drive.
The Chatroom says that turning off fast startup in Windows 10 could speed up the boot process in that Dell. There's also a suggestion that a graphics driver could be causing it. Matthew should check out this article by Expert Reviews on the problem. Sometimes a clean install of Windows 10 will work. If he's doing that, Leo says he should get the SSD first.