The fact that almost all known modifications of Windows in a certain sense are extremely unstable in operation is known to everyone. The worst option is the impossibility of starting the system when a window with the System Recovery Options appears on the screen, and the boot process at this moment freezes tightly, prompting the user to make some decision to restore the operating system. Let's try to figure out how to restore Windows to working order using such system tools.
System Recovery Options: what to do when a system boot error window appears?
The very first and correct solution would be to use an additional dialog of the same name, which appears after the main window with OS recovery options, when one of the menu items is activated. But don't rush! It is possible that the failureshort-term and so far no drastic measures can be resorted to.
First, try to simply force restart your computer. If the situation is not corrected, and the Windows System Recovery Options window appears again, restart the terminal or laptop again, then immediately after the start screen disappears, press the F8 key and call up the additional menu.

In it, it is best to either use the Last Known Good Configuration, or try to start in safe mode, and then use the rollback tools already in the booted system, which are located in the "Control Panel". This solution is applicable only for systems of the seventh version and below.
In the case of the "eight" and "ten", in which the call to this menu by pressing F8 is disabled, you will have to boot from a removable drive with the distribution. If the system starts in Safe Mode, you can use additional boot options or restart with the Shift key pressed.
System Recovery Options in Windows 7: Start Recovery Methods
But it can be assumed that the automatic recovery did not work, or the safe start also failed.

In the boot menu options, go to the troubleshooting item, and then from the System Recovery Options window, select boot recovery. If system components or a hard drive partition onwhich reserves space for storing restore points and he althy images are intact, this might work.
If that doesn't help, instead of Startup Repair from the System Recovery Options menu, select System Recovery, then manually expand the list with all available rollback points and confirm using one of them.
Almost the same actions can be performed when choosing a restore point from a backup. If it was created automatically, or if you created it yourself at some point, this might work.
Note: if the above actions do not work during a stationary boot, use the boot drive with the distribution kit or the LiveCD environment, select the recovery point at startup, and then apply one of the suggested methods. By the way, starting from bootable media is the best option for any action in such a situation.
The Shell Toolkit
Now let's assume the worst - none of the proposed methods to restore the system did not allow. In such a situation, the most acceptable solution is to use the command console toolkit, which can be launched from the main System Recovery Options menu. If the problem is a damaged bootloader, you can restore its functioning using the special tool Bootrec.exe. Enter this command in the console, and then enter / fixmbr separated by a space. After that, enter the main command again, and after it, also add a space after it/fixboot.

In theory, after executing these two commands, the system will come to its senses. If this does not help, call the command console again and completely rewrite the bootloader in it by entering the /rebuildbcd attribute after the main command (the right slash is required to enter all three commands). After performing a restart in a running OS, or even if it does not boot again, check and restore system components using the sfc /scannow.
Windows 10 Features
The tenth modification turned out to be extremely successful in the sense that it is not necessary to restore it using the methods described above.

If the damage has reached a critical threshold, but the OS itself can boot using a safe start, the easiest way is to perform a hard reset using the appropriate tool in the recovery section from the options menu.

But so that neither installed programs nor your user files are destroyed during the rollback process, in a running system, connect the media with the distribution kit or mount the image into a virtual drive (double-click on the file), and then run installer manually (the Setup.exe file in the root of the disk), after which, at the stage of choosing the installation option, check the box to save the requireddata.