following many hours on the phone with my ISP it would appear that I need to reinstall Windows
Do you understand, and can you explain ,exactly
why this needs to be done: what is broken, and what will reinstalling fix?
If not then it may not be a useful thing to do. It is, I am afraid, very commonplace indeed for "technical support" people to tell you to "reinstall Windows" just because it's the first thing on their script and it will get you to shut up and go away, usually for many hours. Getting the ISP's help desk PFY to stop parotting "reinstall Windows" and actually listen to you and actually believe you when you tell them that the problem is at their end does sometimes take a very very long time indeed, yes.
There are few problems for which "reinstalling Windows" is necessary, and even fewer for which it will actually work.