I lost my admin privileges in a bad postgress installation: I lost my admin privileges in Bad Postgres Installation

I did progress, because I active the adminsitrator account and I had privileges to create a new account.

But nor adminsitrator nor new admin account can view and access "C:"

I saw in How to create user account in command prompt in windows 7 the command:

net share concfg*C:\/grant:useraccountname,full

But the win8 retorns that the sintax is wrong.....what is the right command ?

Can the two users access the c: ????