Guide to Remove 1-855-557-3627 Scam Pop-up Effectively

Visited a blog I had never been to and got a window that says:

"Warning!! OS Crash Report Due to a third party application your operating system is crashed. Contact Support for Immediate Fix 1-855-557-3627 (toll free)"

There is an OK button but nothing makes the window go away and the browser is completely unresponsive. Help!