If you try to run Microsoft Word and it crashes before it even opens, look for a normal.dot or normal.dotx file in your user profile and rename it to normal.dotm.old. Then try restarting Word.
On Windows XP this file can usually be found in:
C:\Documents and Settings\<username>\Application Data\Microsoft\Templates
On Windows Vista and Windows 7 this file can usually be found in:
C:\Users\<username>\AppData\Roaming\Microsoft\Templates
I’m amazed at how often this fixes the problem.