An MS Word document is simply more than what you comprehend. It can be referred as a compound file. It comprises of four basic parts, viz. embedded objects, content, header, and summary. To work flawlessly, MS Word requires all these objects to perform efficiently.
While opening, MS Word checks the file format, which may be .doc, .docx, rtf, .txt etc. However, when the format is incorrect, MS word attempts to convert it to a form that can be read and understood.
After recognizing format or after converting it, Word moves to craft the Word object model. The data present in the document forms its basis. All objects like sections, paragraphs, and fields that are later used to perform some operations like printing, viewing etc, are made a part of the document. Though, conversion of the format is not possible in every case. This is because sometimes a document doesn’t open owing to corruption.
Corruption in the Word document can occur due to several reasons such as Macro virus, Invalid digital signature issue or Invalid Macro. Missing or partial data streams, header corruption are some other certain problems that may halt the working of a Word document. But again, the most common reason of corruption could be the bug in application itself which restricts content storage in the document, as a result of which it may fail to get opened correctly.
There is also a problem, what we call as round-tripping that may corrupt the document. It happens with the repetitive conversion of document in and out of Word formats. In some such situations, the data is converted in such a way that its tolerance level degrades and results into corruption. At this point of time, your document requires word repair.
The document corrupted in any of the above mentioned cases can be retrieved by using Word recovery software. The process of Word Recovery is done with exceptional care so that all your data can be recovered from the corrupted Word document.

As we know that Microsoft Word 2003 is a better and secure version, when compared to its predecessors. It introduces various features, like document comparison, reading layout view, Research Task Pane, improved change-tracking and more other features. You might observe several issues comes while trying to open a Word 2003 document. This might occur due to several reasons. One of the most is document corruption, to solve which you will need to use your recent file backup or repair it using Word Repair applications.
As an instance, you might observe any of the below symptoms while attempting to open a Word 2003 document:

Cause
Word 2003 exhibits the above behavior in one of the following conditions:
Document is read-only
Links or the document is damaged
Solution
You need to ensure for appropriate file permissions. If this is not the case, try repairing the damaged Word 2003 document using these methods:

Use third-party Stellar word repair applications to scan and repair the Word 2003 document
Word Recovery tools come embedded with advanced scanning features to allow safe and complete Word document repair.

Having worked diligently on one of my thesis, when I decided to submit it, I thought of taking one last look. After all, revising your work to reduce the mistakes is always a good idea. But, the document refused to open! Instead the computer stopped responding when I booted it! I didn't know whether to be happy that I had not submitted the file in such a state, or should I be upset that all my work was not accessible, probably lost! I had worked hard, but it was all lost. A friend suggested to me that word recovery tool was possible!

Bewildered, I went to his place, and I discussed things at hand. He told me, he had faced similar problem once and had been able to repair the document and thus perform Word recovery. We went to my place and booted the system. What followed was a journey of major ups and downs.

And sure enough, it did work in my case as well. Though he had suggested to me earlier too, but I was apprehensive about it. Now, being the last resort, I opted for it, as my thesis was very important.