Thanks Rhinobull, that's what I wanted
I'll remember to search API functions
Here's the code in case someone need it
Code:
'General Declarations
Option Explicit
Public Declare Function GetUserName Lib "advapi32.dll" Alias "GetUserNameA" (ByVal lpBuffer As String, nSize As Long) As Long
Dim GUNlpBuff As String * 255
Dim GUNret As Long
Dim GUNUserName As String
.
.
.
Private Sub Form_Load()
GUNret = GetUserName(GUNlpBuff, 255)
GUNUserName = Left(GUNlpBuff, InStr(GUNlpBuff, Chr(0)) - 1)
MsgBox GUNUserName
End Sub