My Administrator account is password protected.
1) Check in the user profile if it is a member of administrator.
Yup, checked that. Theres only "Users" in it.
2) Check in the Administrator group if the user is there, just in case.
Yup, checked. Not there.
3) Create another user with Limited access and check if it has the same issue.
Yep, tried that too. Any new limited user account can access anything!
Some more info which may be of use:
Under Administrator group, members are:
NT AUTHORITY\SERVICE (S-1-5-6)
Under Users group, Members are:
NT AUTHORITY\Authenticated Users (S-1-5-11)
NT AUTHORITY\INTERACTIVE (S-1-5-4)
Hope that helps. Im wondering if a Group Policy has changed, but I looked under gpedit.msc and couldnt find a policy specific to Users.