How can I regain full access to my Windows 8 computer after a refresh?

http://ift.tt/1iZHv9S

I got a Blackscreen on my other computer when I returned from a break. So in the end I did a Windows refresh. Now the PC works but I cannot access c drive, I cannot install any programs, and I cannot create any system restore points or create any new user profiles/change administrator privileges, etc.

What do I do please?

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