How to get MS Office version installed on the machine

Think about what you are asking and you will find that you have more or less answered your own question. Simply put, the the product name is really dependent on the values for the version numbers of the executables for Access, Excel, PowerPoint, Word, etc.

That siad, according to theMS article Application Registration, you should be able to find the application executable under the key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\App Paths

Problem is at this point we are unsure of the what the MS Office executable is, so a quick search of the registry for 'office 2010' and one of the results pointed me to ois.exe (C:\PROGRA~2\MICROS~2\Office14\OIS.EXE) but as you can see in the screen shot below, the only thing that identifies this as Office 2010 is the 'Product Name' and 'Description' attributes of the file:

To iterate extended file attributes, use Shell.Applicaiton to bind to the files parent folder, then the file to get a list of the extended file attributes:

GetFileDetails "C:\Program Files (x86)\Microsoft Office\Office14", "OIS.EXE"

Sub GetFileDetails(sFilePath, sFileName)
   
   Dim shell : Set shell = CreateObject("Shell.Application")
   Dim arrHeaders(34), fileInfo, folder, folderItem, i
   
   Set folder = shell.Namespace(sFilePath)
   Set folderItem = folder.ParseName(sFileName)
   
   If (Not folder Is Nothing) Then
      For i = 0 To 34
         arrHeaders(i) = folder.GetDetailsOf(folder.Items, i)
      Next
      
      Set folderItem = folder.ParseName(sFileName)
      
      If (Not folderItem Is Nothing) then
         For i = 0 To 34        
            fileInfo = folder.GetDetailsOf(folderItem, i)
            
            If aqString.GetLength(fileInfo) > 0 Then
               Log.Message arrHeaders(i) & ":" fileInfo
            End If
         Next
      End If
            
      Set folderItem = Nothing
   End If

   Set shell = Nothing

End Sub