What is the problem? a re-installation or repair may make not difference.
Speaking off repair, have you tried to repair IE by going to, Control Panel > Add/Remove Programs > IE add/remove button > Repair Installation. The presenation may differ slightly for you but the basics remain.
Knee jerk coming up: Have you considered using a different browser such as, Mozilla Firefox, Mozilla (full suite with emal, etc), Opera? They pose less of a security risk than IE and it's email companion Outlook Express (OE).
Cheers Murray P