Windows 10: I changed permissions on all files on C: drive now I get black screen

Windows 10
In Windows Explorer, I right-clicked on C: and went to Properties and then selected the Security tab and edited the permissions to Allow Full control and it ran for a long, long time. When I re-booted the computer it works fine until after the Sign In screen then the screen goes black. I have a cursor and if I hit Ctrl-Atl-Delete I can select Task Manager but then the screen goes black again. I can boot into Safe Mode with Networking and I can get a Command Prompt in Safe Mode. I have looked at ICACLS but I'm not sure how to use it to re-set the permissions back to normal Windows 10 settings.
Anybody have any ideas?

:)

 

Am I being hacked/ Changed C: Drive Permissions

I'm having issues with unauthorised permission given to Authenticated Users on my C: drive, some how its has given special permissions to Authenticated Users and grayed out so I cant change and now all folder's in my C: drive belong to (S-1-5-21-1800742781-42368032-4135958153-1003)
instead of (Administrators (User\Administrators))

This leads me to think I have been hacked as well as I am being denied access to a number of folders in C: drive that i used to have Access to

P.S there is something called wormgr.exe accessing the internet from C: Drive

 

Am I being hacked/ Changed C: Drive Permissions

Are you sure it is not wermgr.exe - this is Windows Error Reporting probably reporting errors back to Microsoft!

With respect to S-1-5-21-1800742781-42368032-4135958153-1003, that could refer to your User Account, it is hard to know as each account has a different ID

Do you have permission to create a new folder on your C Drive?

What folders on your C Drive can you now not access that you previously had access to?

 

In order to use ICACLS to restore the permissions. You'd have to run it to save all the permission settings to a file before you change the permissions. I gues you are stuck.

Try to do a system restore before you made the change to see if it helps.

 

I tried system restore, no luck. I can run "takeown" from a command prompt in Safe Mode but can I use that to reset permissions back to default, whatever the default was?

 

One does not simply mess around with the permissions settings of C:\ Drive. You have put your system willingly at risk. *Smile

If system restore is not working, try to repair the system or do a C:\ Drive format and install windows back in.
You wont lose data on the other partitions this way. But take a back up always just in case if any thing goes wrong.

 

I gave up and reformatted the hard drive and installed Windows 7