I recently had an issue on my machine where the following add-ons were crashing IE on my machine when visiting our CRM and SharePoint online sites respectively. I've disabled both add-ons for IE and the crashing has stopped.

Add-on:
NameCtrl Class. Caused IE to crash on many pages of CRM online. http://msdn.microsoft.com/en-us/library/office/ms455335(v=office.14).aspx
Sharepoint Stssync Handler. Caused IE to crash instantly on SharePoint online. http://msdn.microsoft.com/en-us/library/office/ms456225(v=office.14).aspx