Const HKEY_CURRENT_USER = &H80000001

1.  WMI is Windows Management Instumentation.  It's Microsoft's
implementation of Web Based Enterprise Management (WBEM).  It basically
gives you access to aspects of the PC that can be managed.  In the script,
where I've got strComputer = ".", you're asking to look at the local PC but
using WMI you can just as easily check on or alter other computers in your
network.  You can read and write to the registry, read and write to the file
system, check on hardware, processes, services, etc. and monitor events
(when a service starts or stops for example).

2.  Jezebel has provided a good example of using the API

3.  You can run regedit from VBA but I've always found it tough to isolate
the subkeys from the resulting text file unless you have a pretty good idea
what was there before you start.  It can be done but I don't think it is the
most simple approach.  You would use VBA's Shell function to run regedit.
Regedit would need to be run with the "/e" switch to export a reg file.
Something like:
Shell regedit.exe /e Temp.reg HKEY_CURRENT_USER\SOFTWARE
Then you would work with the text file, Temp.reg.

Steve Yandl

Option Explicit

Private Type FILETIME
   dwLowDateTime As Long
   dwHighDateTime As Long
End Type

Private Declare Function RegOpenKeyEx Lib "advapi32.dll" Alias
"RegOpenKeyExA" (ByVal hKey As Long, ByVal lpSubKey As String, ByVal
ulOptions As Long, ByVal samDesired As Long, phkResult As Long) As Long
Private Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long)
As Long
Private Declare Function RegEnumKeyEx Lib "advapi32.dll" Alias
"RegEnumKeyExA" (ByVal hKey As Long, ByVal dwIndex As Long, ByVal lpName As
String, lpcbName As Long, lpReserved As Long, ByVal lpClass As String,
lpcbClass As Long, lpftLastWriteTime As FILETIME) As Long

Const HKCR = &H80000000
Const HKCU = &H80000001
Const HKLM = &H80000002
Const HKKU = &H80000003
Const HKPD = &H80000004
Const HKCC = &H80000005
Const HKDD = &H80000006
Const KEY_ENUMERATE_SUB_KEYS = &H8

Private Sub XXX()

Dim keyname As String     ' Receives keyname for each subkey
Dim keylen As Long        ' Length of keyname
Dim classname As String   ' Receives class name for each subkey
Dim classlen As Long      ' Length of classname
Dim lastwrite As FILETIME ' Receives last-write-to time
Dim handle As Long        ' handle to the opened key
Dim index As Long         ' Index counter
Dim rval As Long          ' Return value
Dim oupval As String

oupval = "Sub-Keys are " & Chr(13)

rval = RegOpenKeyEx(HKCU, "", 0, KEY_ENUMERATE_SUB_KEYS, handle)
If rval <> 0 Then
   MsgBox "Registry key could not be opened."
   Exit Sub
End If

Do While rval = 0  ' Continue if success
   keylen = 255
   keyname = Space(keylen)
   classlen = 255
   classname = Space(classlen)
   rval = RegEnumKeyEx(handle, index, keyname, keylen, ByVal 0, classname,
classlen, lastwrite)
   If rval = 0 Then
       keyname = Left$(keyname, keylen)
       Debug.Print "HKCU\" & keyname
   End If
Loop  ' End the loop
rval = RegCloseKey(handle)

End Sub