The laptop is as good as dead - you restart it, come to the Windows 8 start screen and then everything freezes! You can't do anything, you can't even do it on the desktop!
Backup available?
Reinstalling the operating system can help
The problem is that there's really important data on the laptop and that there's no backup…
Have you ever tried to put the data on something else and to make backups and not play with fire
Get an installation medium (DVD or USB stick) and let the installer repair it, it sometimes finds something.
It can of course also be a hardware defect, but I wouldn't assume that at first. Nevertheless, you can test it with a live boot medium (e.g. Linux), if it starts and works well, it is probably not a hardware defect.
You also have the direct opportunity to save some data.
Then it can of course still be a defective Windows, which can also be caused by a hardware error. If the installation medium does not find anything, the only solution is to reinstall Windows without specialist knowledge and a lot of time.
Remove the hard drive, operate it externally on a second device, hope that the data can be saved, otherwise everything is gone.
