I installed a demo version of Mathematica 10 on a pc running Windows 7 professional 64 bit. When I started the software in went into an endless “Formatting Notebook” and never did start properly. I understand others have had this problem. How do I fix it?
Usually, this is associated with a large notebook or the Mathematica front end is struggling with too many things going on.
Try resetting the initialization files (Wolfram Support Quick Answers: How do I fix common problems by resetting Mathematica 14.0 to its default configuration?).
If that does not correct the problem, contact Technical Support (support@wolfram.com). Tell them how you start Mathematica, the symptoms (example: how long does Mathematica stay in this state), and include your Activation Key or License Number. It would be useful to know if you can run the Mathematica Kernel (Wolfram Support Quick Answers: How do I run the Wolfram Language kernel?).
I emailed tech support. You are just much more responsive than they are. At stackexchange.com the suggestion was to remove wireless components so I installed the demo on my laptop that has a hard-wired monitor, keyboard, and touchpad, and running Widows 7, 64 bit. Mathematica 10 worked perfectly. No way to do this with my desktop.