Private Declare Function GetUserName Lib "advapi32.dll" Alias "GetUserNameA" (ByVal lpBuffer As String, nSize As Long) As Long
Private Sub Command1_Click()
Dim lngRet As Long
Dim strUser As String
strUser = Space(125)
lngRet = GetUserName(strUser, Len(strUser))
If lngRet Then
MsgBox "UserName: " & strUser
End If
End Sub