No worries. Ok so I've tried the 4 steps you suggested, and it did do an update and it said it installed the Telerik ASP.NET AJAX VSExtensions successfully, but still nothing is appearing the in the toolbox. I tried to run the toolbox configuration utility after that to see if it would do anything, and VS2017 did restart but nothing changed. I tried going through the choose items method once more and it tells me the files were "successfully added but are not enabled in the active designer". So I'm being told everything was installed fine, but then my toolbox doesn't show any of the telerik tools.
Any other ideas for what could check or try? I'm using .NET 4.5 so I don't think that's the issue, but I'm not sure what the issue could be.