The only reason I can think of that switching ISPs could affect your access to a particular website would be if, for some strange reason, the default DNS servers used by your new ISP couldn't access that site. (If, unusually, that turns out to be the problem, it's easy enough to fix by switching to different DNS servers but I'll leave out the detail for the moment).
A far more common problem with one or more individual websites refusing to load on a computer is when the browser is trying to use redundant data from its cache. So the first thing to try is using a different browser. (As you've got Windows 10, you've already got both Edge and Internet Explorer available to you and you might well have installed something like Chrome or Firefox as well. Simply try any other browser than the one you normally use).
If switching browsers fixes the problem for you then probably all you need to do is to clear the cache on your regular browser. (Instructions available on request - remember to tell us which browser it is!)
If switching browsers, and subsequently clearing the cache on your regular browser, doesn't fix the problem, then we'll have to investigate further.