' This module reads and writes registry keys.  Unlike the
' internal registry access methods of VB, it can read and
' write any registry keys with string values.

'---------------------------------------------------------------
'-Registry API Declarations...
'---------------------------------------------------------------
Private Declare Function RegCloseKey Lib "advapi32" (ByVal hKey As Long) As Long
Private Declare Function RegCreateKeyEx Lib "advapi32" Alias "RegCreateKeyExA" (ByVal hKey As Long, ByVal lpSubKey As String, ByVal Reserved As Long, ByVal lpClass As String, ByVal dwOptions As Long, ByVal samDesired As Long, ByRef lpSecurityAttributes As SECURITY_ATTRIBUTES, ByRef phkResult As Long, ByRef lpdwDisposition As Long) As Long
Private Declare Function RegOpenKeyEx Lib "advapi32" Alias "RegOpenKeyExA" (ByVal hKey As Long, ByVal lpSubKey As String, ByVal ulOptions As Long, ByVal samDesired As Long, ByRef phkResult As Long) As Long
Private Declare Function RegQueryValueEx Lib "advapi32" Alias "RegQueryValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal lpReserved As Long, ByRef lpType As Long, ByVal lpData As String, ByRef lpcbData As Long) As Long
Private Declare Function RegSetValueEx Lib "advapi32" Alias "RegSetValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal Reserved As Long, ByVal dwType As Long, ByVal lpData As String, ByVal cbData As Long) As Long

'---------------------------------------------------------------
'- Registry Api Constants...
'---------------------------------------------------------------
' Reg Data Types...
Const REG_SZ = 1                         ' Unicode nul terminated string
Const REG_EXPAND_SZ = 2                  ' Unicode nul terminated string
Const REG_DWORD = 4                      ' 32-bit number

' Reg Create Type Values...
Const REG_OPTION_NON_VOLATILE = 0       ' Key is preserved when system is rebooted

' Reg Key Security Options...
Const READ_CONTROL = &H20000
Const KEY_QUERY_VALUE = &H1
Const KEY_SET_VALUE = &H2
Const KEY_CREATE_SUB_KEY = &H4
Const KEY_ENUMERATE_SUB_KEYS = &H8
Const KEY_NOTIFY = &H10
Const KEY_CREATE_LINK = &H20
Const KEY_READ = KEY_QUERY_VALUE + KEY_ENUMERATE_SUB_KEYS + KEY_NOTIFY + READ_CONTROL
Const KEY_WRITE = KEY_SET_VALUE + KEY_CREATE_SUB_KEY + READ_CONTROL
Const KEY_EXECUTE = KEY_READ
Const KEY_ALL_ACCESS = KEY_QUERY_VALUE + KEY_SET_VALUE + _
                       KEY_CREATE_SUB_KEY + KEY_ENUMERATE_SUB_KEYS + _
                       KEY_NOTIFY + KEY_CREATE_LINK + READ_CONTROL
                     
' Reg Key ROOT Types...
Const HKEY_CLASSES_ROOT = &H80000000
Const HKEY_CURRENT_USER = &H80000001
Const HKEY_LOCAL_MACHINE = &H80000002
Const HKEY_USERS = &H80000003
Const HKEY_PERFORMANCE_DATA = &H80000004

' Return Value...
Const ERROR_NONE = 0
Const ERROR_BADKEY = 2
Const ERROR_ACCESS_DENIED = 8
Const ERROR_SUCCESS = 0

'---------------------------------------------------------------
'- Registry Security Attributes TYPE...
'---------------------------------------------------------------
Private Type SECURITY_ATTRIBUTES
    nLength As Long
    lpSecurityDescriptor As Long
    bInheritHandle As Boolean
End Type


'-------------------------------------------------------------------------------------------------
'sample usage - Debug.Print UpodateKey(HKEY_CLASSES_ROOT, "keyname", "newvalue"
'-------------------------------------------------------------------------------------------------
Public Function UpdateKey(KeyRoot As Long, KeyName As String, SubKeyName As String, SubKeyValue As String) As Boolean
    Dim rc As Long                                      ' Return Code
    Dim hKey As Long                                    ' Handle To A Registry Key
    Dim hDepth As Long                                  '
    Dim lpAttr As SECURITY_ATTRIBUTES                   ' Registry Security Type
    
    lpAttr.nLength = 50                                 ' Set Security Attributes To Defaults...
    lpAttr.lpSecurityDescriptor = 0                     ' ...
    lpAttr.bInheritHandle = True                        ' ...

    '------------------------------------------------------------
    '- Create/Open Registry Key...
    '------------------------------------------------------------
    rc = RegCreateKeyEx(KeyRoot, KeyName, _
                        0, REG_SZ, _
                        REG_OPTION_NON_VOLATILE, KEY_ALL_ACCESS, lpAttr, _
                        hKey, hDepth)                   ' Create/Open //KeyRoot//KeyName
    
    If (rc <> ERROR_SUCCESS) Then GoTo CreateKeyError   ' Handle Errors...
    
    '------------------------------------------------------------
    '- Create/Modify Key Value...
    '------------------------------------------------------------
    If (SubKeyValue = "" Then SubKeyValue = " "        ' A Space Is Needed For RegSetValueEx() To Work...
    
    ' Create/Modify Key Value
    rc = RegSetValueEx(hKey, SubKeyName, _
                       0, REG_SZ, _
                       SubKeyValue, LenB(StrConv(SubKeyValue, vbFromUnicode)))
                       
    If (rc <> ERROR_SUCCESS) Then GoTo CreateKeyError   ' Handle Error
    '------------------------------------------------------------
    '- Close Registry Key...
    '------------------------------------------------------------
    rc = RegCloseKey(hKey)                              ' Close Key
    
    UpdateKey = True                                    ' Return Success
    Exit Function                                       ' Exit
CreateKeyError:
    UpdateKey = False                                   ' Set Error Return Code
    rc = RegCloseKey(hKey)                              ' Attempt To Close Key
End Function

'-------------------------------------------------------------------------------------------------
'sample usage - Debug.Print GetKeyValue(HKEY_CLASSES_ROOT, "COMCTL.ListviewCtrl.1\CLSID", ""
'-------------------------------------------------------------------------------------------------
Public Function GetKeyValue(KeyRoot As Long, KeyName As String, SubKeyRef As String) As String
    Dim i As Long                                           ' Loop Counter
    Dim rc As Long                                          ' Return Code
    Dim hKey As Long                                        ' Handle To An Open Registry Key
    Dim hDepth As Long                                      '
    Dim sKeyVal As String
    Dim lKeyValType As Long                                 ' Data Type Of A Registry Key
    Dim tmpVal As String                                    ' Tempory Storage For A Registry Key Value
    Dim KeyValSize As Long                                  ' Size Of Registry Key Variable
    
    ' Open RegKey Under KeyRoot {HKEY_LOCAL_MACHINE...}
    '------------------------------------------------------------
    rc = RegOpenKeyEx(KeyRoot, KeyName, 0, KEY_ALL_ACCESS, hKey) ' Open Registry Key
    
    If (rc <> ERROR_SUCCESS) Then GoTo GetKeyError          ' Handle Error...
    
    tmpVal = String$(1024, 0)                             ' Allocate Variable Space
    KeyValSize = 1024                                       ' Mark Variable Size
    
    '------------------------------------------------------------
    ' Retrieve Registry Key Value...
    '------------------------------------------------------------
    rc = RegQueryValueEx(hKey, SubKeyRef, 0, _
                         lKeyValType, tmpVal, KeyValSize)    ' Get/Create Key Value
                        
    If (rc <> ERROR_SUCCESS) Then GoTo GetKeyError          ' Handle Errors
      
    tmpVal = Left$(tmpVal, InStr(tmpVal, Chr(0)) - 1)

    '------------------------------------------------------------
    ' Determine Key Value Type For Conversion...
    '------------------------------------------------------------
    Select Case lKeyValType                                  ' Search Data Types...
    Case REG_SZ, REG_EXPAND_SZ                              ' String Registry Key Data Type
        sKeyVal = tmpVal                                     ' Copy String Value
    Case REG_DWORD                                          ' Double Word Registry Key Data Type
        For i = Len(tmpVal) To 1 Step -1                    ' Convert Each Bit
            sKeyVal = sKeyVal + Hex(Asc(Mid(tmpVal, i, 1)))   ' Build Value Char. By Char.
        Next
        sKeyVal = Format$("&h" + sKeyVal)                     ' Convert Double Word To String
    End Select
    
    GetKeyValue = sKeyVal                                   ' Return Value
    rc = RegCloseKey(hKey)                                  ' Close Registry Key
    Exit Function                                           ' Exit
    
GetKeyError:    ' Cleanup After An Error Has Occured...
    GetKeyValue = vbNullString                              ' Set Return Val To Empty String
    rc = RegCloseKey(hKey)                                  ' Close Registry Key
End Function

МП41А... Помню, были раньше у нас такие советские транзисторы

sub demo()
dim result as long
dim theValue as string
dim lngValueLength as long
strValue = "Проверка"
lngValueLength = len(strValue)
RegOpen HKEY_LOCAL_MACHINE, "software\demo\previev", result 'Константы и функции Win32 API прдварительно объявлены
RegSetValueEx result, "Проверка", 0, REG_SZ, strValue, lngValueLength
end sub

Private Declare Function RegSetValueEx Lib "advapi32.dll" Alias "RegSetValueExA" (ByVal hKey As Long, ByVal lpValueName As String, ByVal Reserved As Long, ByVal dwType As Long, ByVal lpData As String, ByVal cbData As Long) As Long        ' Note that if you declare the lpData parameter as String, you must pass it By Value.
Private Declare Function RegOpenKey Lib "advapi32.dll" Alias "RegOpenKeyA" (ByVal hKey As Long, ByVal lpSubKey As String, phkResult As Long) As Long
Private Declare Function RegCloseKey Lib "advapi32.dll" (ByVal hKey As Long) As Long
Private Const REG_SZ = 1                         ' Unicode nul terminated string
Private Const HKEY_CURRENT_USER = &H80000001

Private Sub Command1_Click()
    res$ = "Значение параметра"
    Print RegOpenKey(HKEY_CURRENT_USER, "Environment", rc&
    Print RegSetValueEx(rc&, "Проверка", 0, REG_SZ, res$, Len(res$) + 1)
    Print RegCloseKey(rc&
End Sub