Just for the record, I've had that (and similar) splash/warning page come up a few times.
The first couple times, I simply turned off my computer.
No damage done either time.
Then I started seeing what else I could do...
apparently the program NEEDS you to click on something on that page to execute.
I've even gone so far as to finish what I was doing in other browser windows before restarting my machine.
Hasn't gotten me yet (of course, now that I've said all that.....)