Private Sub Form_Load()
MsgBox IIf(Dir("c:\windows", vbDirectory) <> "", "", "no ") & "existe"
End Sub

Option Explicit
Private Const CSIDL_PERSONAL As Long = &H5
Const MAX_PATH = 260
Private Type SHITEMID
cb As Long
abID As Byte
End Type
Private Type ITEMIDLIST
mkid As SHITEMID
End Type
Private Declare Function SHGetSpecialFolderLocation Lib "shell32.dll" (ByVal hwndOwner As Long, ByVal nFolder As Long, pidl As ITEMIDLIST) As Long
Private Declare Function SHGetPathFromIDList Lib "shell32.dll" Alias "SHGetPathFromIDListA" (ByVal pidl As Long, ByVal pszPath As String) As Long

Private Sub Form_Load()
Dim Path As String
Path = MisDocumentos(CSIDL_PERSONAL)
If Path <> vbNullString Then
MsgBox Path
End If
End Sub

Private Function MisDocumentos(CSIDL As Long) As String
Dim ret As Long
Dim IDL As ITEMIDLIST
Dim Path As String
ret = SHGetSpecialFolderLocation(100, CSIDL, IDL)
If ret = 0 Then
Path$ = Space$(512)
ret = SHGetPathFromIDList(ByVal IDL.mkid.cb, ByVal Path$)
MisDocumentos = Left$(Path, InStr(Path, Chr$(0)) - 1)
Exit Function
End If
MisDocumentos = vbNullString
End Function