Before attempting to repair the corrupted template, close all your existing Ms Word documents and start Word without templates. For that to happen, hit Start, Run and type winword.exe /a. If your Word opens in normal mode, you will have to follow the next steps. Try renaming your Normal template. The normal template for Word 2007 is normal.dotx or normal.dotm, while for Word 2003, the normal template is Normal.dot. So, rename it as Normal.old. Normal.dot is stored in different places depending on which version of Microsoft Word and which version of Windows you have.
The second solution is to try to repair your Microsoft Office package. If you want to do this, select Start from your taskbar, go to Control Panel, choose Add or Remove Programs, select Change and go to Reinstall or Repair Microsoft Office to its original state.