The ccleaner is erasing the important Windows 10 registry, it is rendering the operating system unusable.
Even after redoing the action with the backup done.
I ask you to analyze the version of Ccleaner because the program is damaging Windows
The ccleaner is
is there a reason why you ran the registry cleaning portion of CC?
usually, unless your PC has issues, no benefit is gained by cleaning the registry.
(and as you have discovered - lots of potential issues)
if you absolutely have to clean the registry, do it in small chunks.
do not trust a program, even one as gentle as CC, to get it right all the time.
what Windows are you using?
what version of CC?
I've seen Win10 systems act weird after cleaning everything listed as invalid in the registry section of CCleaner - although you really shouldn't be doing that especially without a good backup in place, and I'm not referring to the .REG backup that CCleaner will create I'm referring to a full registry backup such as with System Restore. When the weirdness happens it usually takes several reboots for it to sometimes self-correct some things, and in other instances it requires an automatic update be applied to correct others before it starts acting more-or-less normal again.
Being that Win10 is still relatively new cleaning it's registry in my opinion is something to completely avoid - unless of course it's some specific Microsoft Fixit that is downloaded from Microsoft or from the PC manufacturer to fix a known particular issue.