SECURITY question

 
I have security question.
It happened to be added new user with set:administrator - Windows 2003 server.
Listed:

Path: E:\Programi\MetaTrader 4\terminal.exe
Properties
Security

Group or user names:
Account Unknown(S-1-5-21-823518204-1935655697-682003330-1003)
Administrators(...\Administrators)
SYSTEM
Users(...\Users)

Permission for Account Unknown(S-1-5-21-823518204-1935655697-682003330-1003)
Full Control Allow
Modify Allow
Read & Execute Allow
Read Allow
Write Allow

Does this added user can take files from the MetaTrader Directory?
Part C: Windows 2003: NTFS partition.
Part E: NTFS partition.