IE6 and Outlook express Win xp

I have been having some connection problems in IE 6 and a error message in sending mail in outlook express (“cannot open out Outbox…”) My service provider feels it might be a corupt file in IE 6/outlook. Win xp will not allow removal of IE 6 so I can reinstall. I did a reinstall of xp (not a clean install)and the problem was not corrected. I tried reinstalling outlook express from microsoft website but a message comes up that I have a newer version on my system and cannot continue. Any ideas will help. I really do not want to do a clean install at this time.