You can use Google or, if you want, browse the ‘Links’ page on my signature.
The last one should be the Outlook/Exchange plugin for MS Outlook (not the Express).
When you open it, you will see it active. If MS Outlook is closed, never mind, the plugin is not necessary at that time so, only 4 in 5 possible.
Try browsing the Download Center of Microsoft and search for the product IE 