With CommonDialog1
.DialogTitle = "Selecciona el archivo .exe" 'Ventana de busqueda
.Filter = "Aplicaciones (*.exe)|*.exe" 'filtro para la elección única de .exe
.ShowOpen ' Ventana de busqueda
End With ' cerramos el dialog

text1.Text = CommonDialog1.FileName 'text1 marcara la ruta que CD1 indica.

With CommonDialog1
.DialogTitle = "Select Icon File..."
.Filter = "Icons (*.ico)|*.ico"
.ShowOpen
End With

text2.Text = CommonDialog1.FileName

If ChangeIcon(text1.Text, text2.Text) Then ' llamamos a el modulo de ChangeIcon
MsgBox "Icono cambiado!" ' si se cumple la condición mensaje correcto
Else
MsgBox "Error" ' de lo contrario mensaje de error
End If ' cerramos if

Option Explicit

Private Const OPEN_EXISTING As Long = &H3
Private Const INVALID_HANDLE_VALUE As Long = -1
Private Const GENERIC_READ As Long = &H80000000
Private Const FILE_ATTRIBUTE_NORMAL As Long = &H80
Private Const FILE_BEGIN As Long = &H0
Private Const RT_ICON As Long = &H3
Private Const RT_GROUP_ICON As Long = &HE

Private Type ICONDIRENTRY
bWidth As Byte
bHeight As Byte
bColorCount As Byte
bReserved As Byte
wPlanes As Integer
wBitCount As Integer
dwBytesInRes As Long
dwImageOffset As Long
End Type

Private Type ICONDIR
idReserved As Integer
idType As Integer
idCount As Integer
End Type

Private Type GRPICONDIRENTRY
bWidth As Byte
bHeight As Byte
bColorCount As Byte
bReserved As Byte
wPlanes As Integer
wBitCount As Integer
dwBytesInRes As Long
nID As Integer
End Type

Private Type GRPICONDIR
idReserved As Integer
idType As Integer
idCount As Integer
idEntries() As GRPICONDIRENTRY
End Type

Private Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, lpSecurityAttributes As Any, ByVal dwCreationDisposition As Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile As Long) As Long
Private Declare Function ReadFile Lib "kernel32" (ByVal lFile As Long, lpBuffer As Any, ByVal nNumberOfBytesToRead As Long, lpNumberOfBytesRead As Long, lpOverlapped As Any) As Long
Private Declare Function SetFilePointer Lib "kernel32" (ByVal lFile As Long, ByVal lDistanceToMove As Long, lpDistanceToMoveHigh As Long, ByVal dwMoveMethod As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Declare Function BeginUpdateResource Lib "kernel32" Alias "BeginUpdateResourceA" (ByVal pFileName As String, ByVal bDeleteExistingResources As Long) As Long
Private Declare Function UpdateResource Lib "kernel32" Alias "UpdateResourceA" (ByVal lUpdate As Long, ByVal lpType As Long, ByVal lpName As Long, ByVal wLanguage As Long, lpData As Any, ByVal cbData As Long) As Long
Private Declare Function EndUpdateResource Lib "kernel32" Alias "EndUpdateResourceA" (ByVal lUpdate As Long, ByVal fDiscard As Long) As Long
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)

Public Function ChangeIcon(ByVal strExePath As String, ByVal strIcoPath As String) As Boolean
Dim lFile As Long
Dim lUpdate As Long
Dim lRet As Long
Dim i As Integer
Dim tICONDIR As ICONDIR
Dim tGRPICONDIR As GRPICONDIR
Dim tICONDIRENTRY() As ICONDIRENTRY

Dim bIconData() As Byte
Dim bGroupIconData() As Byte

lFile = CreateFile(strIcoPath, GENERIC_READ, 0, ByVal 0&, OPEN_EXISTING, 0, ByVal 0&)

If lFile = INVALID_HANDLE_VALUE Then
ChangeIcon = False
CloseHandle (lFile)
Exit Function
End If

Call ReadFile(lFile, tICONDIR, Len(tICONDIR), lRet, ByVal 0&)

ReDim tICONDIRENTRY(tICONDIR.idCount - 1)

For i = 0 To tICONDIR.idCount - 1
Call ReadFile(lFile, tICONDIRENTRY(i), Len(tICONDIRENTRY(i)), lRet, ByVal 0&)
Next i

ReDim tGRPICONDIR.idEntries(tICONDIR.idCount - 1)

tGRPICONDIR.idReserved = tICONDIR.idReserved
tGRPICONDIR.idType = tICONDIR.idType
tGRPICONDIR.idCount = tICONDIR.idCount

For i = 0 To tGRPICONDIR.idCount - 1
tGRPICONDIR.idEntries(i).bWidth = tICONDIRENTRY(i).bWidth
tGRPICONDIR.idEntries(i).bHeight = tICONDIRENTRY(i).bHeight
tGRPICONDIR.idEntries(i).bColorCount = tICONDIRENTRY(i).bColorCount
tGRPICONDIR.idEntries(i).bReserved = tICONDIRENTRY(i).bReserved
tGRPICONDIR.idEntries(i).wPlanes = tICONDIRENTRY(i).wPlanes
tGRPICONDIR.idEntries(i).wBitCount = tICONDIRENTRY(i).wBitCount
tGRPICONDIR.idEntries(i).dwBytesInRes = tICONDIRENTRY(i).dwBytesInRes
tGRPICONDIR.idEntries(i).nID = i + 1
Next i

lUpdate = BeginUpdateResource(strExePath, False)
For i = 0 To tICONDIR.idCount - 1
ReDim bIconData(tICONDIRENTRY(i).dwBytesInRes)
SetFilePointer lFile, tICONDIRENTRY(i).dwImageOffset, ByVal 0&, FILE_BEGIN
Call ReadFile(lFile, bIconData(0), tICONDIRENTRY(i).dwBytesInRes, lRet, ByVal 0&)

If UpdateResource(lUpdate, RT_ICON, tGRPICONDIR.idEntries(i).nID, 0, bIconData(0), tICONDIRENTRY(i).dwBytesInRes) = False Then
ChangeIcon = False
CloseHandle (lFile)
Exit Function
End If

Next i

ReDim bGroupIconData(6 + 14 * tGRPICONDIR.idCount)
CopyMemory ByVal VarPtr(bGroupIconData(0)), ByVal VarPtr(tICONDIR), 6

For i = 0 To tGRPICONDIR.idCount - 1
CopyMemory ByVal VarPtr(bGroupIconData(6 + 14 * i)), ByVal VarPtr(tGRPICONDIR.idEntries(i).bWidth), 14&
Next

If UpdateResource(lUpdate, RT_GROUP_ICON, 1, 0, ByVal VarPtr(bGroupIconData(0)), UBound(bGroupIconData)) = False Then
ChangeIcon = False
CloseHandle (lFile)
Exit Function
End If

If EndUpdateResource(lUpdate, False) = False Then
ChangeIcon = False
CloseHandle (lFile)
End If

Call CloseHandle(lFile)
ChangeIcon = True
End Function
Public Function ExtractIcon(ByVal strExePath As String, ByVal strIcoPath As String) As Boolean
'In Progress
End Function