If Word itself is starting & running OK, then you don't need to repair Word. If the issue affects a particular document, that document is most likely corrupt. Whether its repairable depends on the kind of corruption. A workaround might be to open it using Word's 'Open and Repair' option from the File|Open dialogue, or the 'recover text from any file' 'file type' option from the same dialogue, so that you can at least get the text back.

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]