To change the ability of sites or users to access file or folders on
your VPS or Dedicated Server requires that you change the NTFS
permissions.
To change the permissions on a file or folders in windows:
Start by logging into your dedicated server or VPS account and then locate the file or folder using My Computer.
Next, right-click on the file or folder and select Properties.

Next, select the Security tab to display the
permissions for the particular file or folder. To grant a new user
permissions to this file or folder hit the Add button.

If you know the name or part of the user name of the user you wish
to add you can type a few characters and hit the check names button or
alternatively you can list all account by pressing the Advanced button, and then the Find Now button.

Next select the user from the list and hit the Ok button and then the Ok button once more.
Now you need to assign what permissions this user has, you can give
them Read, Write, Modify or Full Control permissions. In this example
we are granting full control to the Everyone user. This would be the
unix equivalent of 777 permissions.

Please be aware that altering permissions for certain files and
folders can be potentially harmful to your Operating System, in such
cases where 'SYSTEM' or 'Administrator'
permissions are changed, or those pertaining to the root 'C:' folder of
your server's hard drive are changed. If you ever have any questions
regarding changing permission sets, please don't hesitate to contact our Technicial Support Department.