Windows 7 goes into reboot. How to diagnose or how to reinstall "on top"?

Question

Windows

OEM WIN7 HB SP1. It goes into reboot a couple of seconds after the mouse cursor appears. No BSOD. There is no \windows\minidump folder. In the system log, the last entries are before the crash (normal shutdown, from errors - disabling shadow copies due to overflow of the system disk), later there are no entries, freed up disk space. Ntbtlog ends up loading kbdhid.sys successfully, no errors. Memtest, checkdisk, Victoria and SFC find no errors. The hardware configuration has not changed. In the wineupdate log for the last day, only windows defender updates. Boot recovery tool does not find errors 4 times out of 5, on the fifth - corrupt ACL recommended by MS "bootrec /rebuild bcd" does not change the situation.
Traditional: no backups, no restore points, installation from scratch is unacceptable.
What else can be done to find out the cause/solution of the problem? Are there ways to reinstall a non-bootable win7 "on top"?

Answer 1

Won. Copying registry files from %windir%\system32\config\regback did not help. I remembered that on Hiren`s bootCD there was a RegistryRestoreWizard utility that allowed you to roll back the registry to one of the points using .LOG registry files.
Rolling back the registry for two days solved the problem.

Answer 2

Safe mode? Maybe this will help?