Significant installation problems

I first installed twenty fourteen and it seemed OK. I tried to set up a child theme (3 times) but each time the web site showed up unformatted. I posted here for assistance but no real support.
So as a last resort I decided to forget about child theme and go back to twenty fourteen as it was. Strangely, the theme doesn’t show up in the Appearance/Manage Themes section. I thought to reinstall via the Search Themes section, but there is shows that it is already installed. Very weird.
I’m at the stage where I’m going to drop twenty fourteen and go for something which works. I’ve installed maybe 15-20 other themes and never had this amount of trouble.