How to compare 2 word documents in C# with out Ms-office installation

hai,

I want to compare 2 word documents in c# sideby side and get Different text or sentences in the word documents(.doc or .docx) as a report and the report can be highlighting the differences in side by side and am using following code

  Application wordApp = new Application();
            wordApp.Visible = true;
            object wordTrue = (object)true;
            object wordFalse = (object)false;
            object fileToOpen = @"D:\MyWorks\test1.doc";
            object missing = Type.Missing;
            Document doc1 = wordApp.Documents.Open(ref fileToOpen,
                   ref missing, ref wordFalse, ref wordFalse, ref missing,
                   ref missing, ref missing, ref missing, ref missing,
                   ref missing, ref missing, ref wordTrue, ref missing,
                   ref missing, ref missing, ref missing);

            object fileToOpen1 = @"D:\MyWorks\test2.doc";
            Document doc2 = wordApp.Documents.Open(ref fileToOpen1,
                   ref missing, ref wordFalse, ref wordFalse, ref missing,
                   ref missing, ref missing, ref missing, ref missing,
                   ref missing, ref missing, ref missing, ref missing,
                   ref missing, ref missing, ref missing);

            Document doc = wordApp.CompareDocuments(doc1, doc2, WdCompareDestination.wdCompareDestinationNew, WdGranularity.wdGranularityWordLevel,
                true, true, true, true, true, true, true, true, true, true, "", true);

the above code giving follwing error


Retrieving the COM class factory for component with CLSID {000209FF-0000-0000-C000-000000000046} failed due to the following error: 80040154 Class not registered (Exception from HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG)).


please help me in this aspect and i want run this in system which does't contain ms-office installed version plese provide some gudilines

thanks