ApplicationClass word = new ApplicationClass();
object m = Missing.Value;
object fileObj = "myfile.docx";
Document doc = word.Documents.Open(ref fileObj, ref m, ref m, ref m, ref m, ref m, ref m, ref m, ref m, ref m, ref m, ref m, ref m, ref m, ref m, ref m);
int red = 0;
for (int i = 1; i <= doc.Words.Count; i++)
{
if (doc.Words[i].Font.Color == WdColor.wdColorRed)
{
red++;
}
}
word.Quit(ref m, ref m, ref m);
word = null;
GC.Collect();