Private Sub Form_Load()
Dim key_name As String

    key_name = "SOFTWARE\Microsoft\VisualStudio"
    txtKeys.Text = _
        key_name & vbCrLf & _
        GetKeyInfo(key_name, 4)
End Sub

The function closes the Registry key and recursively calls itself to examine the subkeys.

' Get the key information for this key and
' its subkeys.
Private Function GetKeyInfo(ByVal key_name As String, ByVal _
    indent As Integer) As String
Dim subkeys As Collection
Dim subkey_values As Collection
Dim subkey_num As Integer
Dim subkey_name As String
Dim subkey_value As String
Dim length As Long
Dim hKey As Long
Dim txt As String

    Set subkeys = New Collection
    Set subkey_values = New Collection
    
    ' Open the key.
    If RegOpenKeyEx(HKEY_LOCAL_MACHINE, _
        key_name, _
        0&, KEY_ALL_ACCESS, hKey) <> ERROR_SUCCESS _
    Then
        MsgBox "Error opening key."
        Exit Function
    End If
    
    ' Enumerate the subkeys.
    subkey_num = 0
    Do
        ' Enumerate subkeys until we get an error.
        length = 256
        subkey_name = Space$(length)
        If RegEnumKey(hKey, subkey_num, _
            subkey_name, length) _
                <> ERROR_SUCCESS Then Exit Do
        subkey_num = subkey_num + 1
        
        subkey_name = Left$(subkey_name, InStr(subkey_name, _
            Chr$(0)) - 1)
        subkeys.Add subkey_name
    
        ' Get the subkey's value.
        length = 256
        subkey_value = Space$(length)
        If RegQueryValue(hKey, subkey_name, _
            subkey_value, length) _
            <> ERROR_SUCCESS _
        Then
            subkey_values.Add "Error"
        Else
            ' Remove the trailing null character.
            subkey_value = Left$(subkey_value, length - 1)
            subkey_values.Add subkey_value
        End If
    Loop
    
    ' Close the key.
    If RegCloseKey(hKey) <> ERROR_SUCCESS Then
        MsgBox "Error closing key."
    End If

    ' Recursively get information on the keys.
    For subkey_num = 1 To subkeys.Count
        txt = txt & Space$(indent) & _
            subkeys(subkey_num) & _
            ": " & subkey_values(subkey_num) & _
            vbCrLf
        txt = txt & GetKeyInfo( _
            key_name & "\" & subkeys(subkey_num), _
            indent + 4)
    Next subkey_num
    
    GetKeyInfo = txt
End Function