See https://support.mozilla.com/en-US/forum/1/399985 and https://support.mozilla.com/nl/forum/1/682558

Check for an extension called The Browser Highlighter in Tools -> Add-ons -> Extensions and disable it.

Edit: I see now from Troubleshooting Information that you do have the problematic extension. This can also cause poor startup performance and other problems in Firefox.

I don't see where to post thanks here. I will try what "rjohnson19" said but I want also to thank him for his time. Mike

For the other part, deleting "_Shim.dll", I would not do it. I prefer to change the browsers (if they don't have a fix) than modifying system files.

I don't know if you didn't see my edit to my above response. But it is definitely the Browser Highlighter extension (this is bundled with Skype and is supposed to have some positive effect on eBay, but instead it causes crashes and slowdowns).

So you won't need to rename any DLL files.

And you're welcome.