Saving word 97 doc as word 2003 doc automatically using c#`

Question

Hi, I have some documents in word 97 format. I want to convert it as word 2003 documents. I can open these documents in word 2003 and perform save as operation. But i need to automate this process through c#, because the no. of documents are very large around 2000. Also I need to compare these documents(97 and 2003 docs)To ensure that they are perfectly correct. Any idea to solve this problem