Unity always crashing on windows 8.1

Complete newbie here so sorry if any questions are dumb ones.

I’m running on a high spec Toshiba with windows 8.1
I downloaded and installed the latest stable release of unity.
Everything was going well using the ‘roller ball’ video tutorial.
Switched to the ‘space shooter’ video tutorial, now unity crashes all the time.
I’ve tried forcing the d3d11, makes no difference.

Any ideas?

Sub questions…

  1. where do I find the log files?
  2. my system has an NVidia gt 740, how can I force unity to use this?

Thanks in advance

I think I have answered my own question…

I wracked my (tiny) brain to try to figure out what had gone wrong, went backwards through the (few) changes I had made to my machine…it turned out zone alarm seems to be incompatible with unity (at least on my set up). I had told zone alarm to give unity every possible permission yet it still crashed ALL the time. Now zone alarm has been uninstalled unity seems to be working fine again …