Hi I'm having trouble with my Dell XPS 9550. I'm currently running Windows 10 Pro and since late August my laptop will not install the cumulative updates Microsoft puts out. It begins to install it and after an hour it gets to 100% and then says update failed uninstalling update and it stays like that for another hour. I've contacted Microsoft over the issue and everything they've tried won't work. I've tried resetting Windows 10 and that fails, reinstalling Windows from a disc image fails, everything fails. I've searched for hours trying to find a solution trying different Commands and system checks in the command prompts and nothing will work.
Similar problem with Dell XPS 8300 (Win 7 converted to 10). For months it's been the spinning wheel on a black screen that won't complete. Usually resolved by restarting many, many times. Neither Dell nor Windows diagnostics suggest a problem. A particularly persistent set of hangups occurred yesterday. This morning, a restart has produced a persistent gray "Getting windows ready, don't turn off your computer" screen. I'll see where it goes.
Update completed after 45 min, I expect to see the black spinning wheel again when the next major Windows patch hits. Or maybe later today. Who knows?
It sounds as though your hard drive may have failed. Have you tried a different, known good hard drive?
If you're still under warranty, you may wish to contact Tech Support for further troubleshooting.