I've run the installer again. It gets to the Feature Selection page, and there I'm stopped.

As you can (I hope) see, the features are all selected, and disabled. When I try clicking on the Next button it complains because I've not selected anything. But it tells me that everything is selected. I'm confused; either it's all selected and installed and I can go on, but it won't let me.

Addendum: OK, I tried to put a link to a picture I captured of the dialog box, first on SkyDrive and then on Flickr, but in each case it fails. I don't know why, but it does. So, here's the URL, sorry, you'll have to copy-and-paste into your browser's address bar.

https://www.sqlservercentral.com/Forums/Uploads/image-unavailable.png