Pb between Office 2003 & Visio 2003

I installed Office 2003 on XP profesional. It worked fine until I installed Visio 2002. After this, I had a lot of pb with my station: I couldn't go to start - run. Windows update didn't work and many messages in Outlook can't be read, (They are on an exchange server). Microsoft suggest to install XML Parser to fix the pb with windows update. It works for this and for the run command but it doesnt fix the Outlook pb and many other minor bugs.
Someone has a solution?