I installed the deprecated server behaviors first, then the MySQLi extension, and it has been working happily fora while - I was enjoying learning how to get the best out of it. This weekend I had to create two files each with an insert record behavior. It may have been my computer, because also this week the computer stopped working, and I had to re-format the entire hard drive and install a clean version of Windows 10 before it would work.
When I was trying to sort out the pages I was getting errors similar to "script name UNKNOWN has been running for a long time" or something similar, and it was causing it to hang.
Like I said, it probably was the computer dying, but now I have a clean install of 2017 on a newly installed version of Win10 and I am sure that will fix the problem :)