Recently I was working with SharePoint when the browser crashed. I opened my site back up, went to the "create" menu and... BAM! the browser crashed.
Thinking IE was having a "Microsoft Moment" - I opened the site in Firefox. Open the "create" menu and... CRASH!
But Firefox told me something IE didn't - the Silverlight plug-in was misbehaving.
I found this video via Google searches that suggests a number of things to try and get the plug-in to work again.
What ended up working for me was to go to the Silverlight home page (http://www.microsoft.com/silverlight/), save the plug-in to disk, and run it to re-install Silverlight.