VB Forum / Win API / September 2003

As long as you know at least one ProgID, you can do this:

Private Type CLSID          '// GUID
   Data1 As Long
   Data2 As Integer
   Data3 As Integer
   Data4(0 To 7) As Byte
End Type

'// Possible errors
Private Const E_INVALIDARG                     As Long = &H80070057
Private Const E_UNEXPECTED                     As Long = &H8000FFFF
Private Const CO_E_CLASSSTRING                 As Long = &H800401F3
Private Const E_OUTOFMEMORY                    As Long = &H8007000E
Private Const REGDB_E_WRITEREGDB               As Long = &H80040151

Private Declare Function CLSIDFromProgID Lib "ole32" (ByVal lpszProgID As
String, pclsid As CLSID) As Long

'
'
'
Private Function IsProgIDRegistered(ByVal strProgID As String) As Boolean

   '// a ProgID goes something like this: "MSComctlLib.Slider". Passing a
   '// bogus value or a non-registered class will return FALSE

   Dim pclsid As CLSID
   Dim hResult As Long

   On Error Resume Next

   hResult = CLSIDFromProgID(StrConv(strProgID, vbUnicode), pclsid)
   IsProgIDRegistered = (hResult = 0)

End Function

And then call it like so:

Private Sub Form_Load()

   Debug.Print IsProgIDRegistered("ADODB.Recordset")
   Debug.Print IsProgIDRegistered("Some.BogusProgid")
   Debug.Print IsProgIDRegistered("MSXML2.DOMDocument")

End Sub