Hi Antony,
Reinstalling rarely fixes anything that a repair won't. Forcing Word to rcreate its Normal template and to clear & re-write its registry keys may help.
To do the former, quit Word, locate the Normal template and delete it. Its location is available in Word, under Tools|Options|File Locations > User Templates.
To do the latter, quit Word, then go to Start|Run and input:
winword /unregserver
when that has executed, input:
winword /regserver
If that doesn't work, try the approaches suggested here:
http://support.microsoft.com/kb/921541
http://word.mvps.org/FAQs/AppErrors/...artingWord.htm and
http://lounge.windowssecrets.com/ind...owtopic=197827
for various series of troubleshooting steps that will help you track down (and hopefully solve) the problem.