After trawling this forum for ages looking for an answer, I found one via my hosting provider 123Reg and it worked for me. I doubt it will solve all problems, but I'm sharing just in case.
1. In your WP admin, go to Settings - > General
2. Delete any colons in the URL for your site except the one that should be in the usual address. e.g. I had to change "http://website:/home" to "http://website/home"
3. Log back into wordpress when it kicks you out.
4. Visual editor should be working.
Please note, I had also disabled all plugins, installed the google libraries and changed the theme to no success. By the time this solution worked for me, I had my plugins and theme back on with just the addition of the Google library plugin.
Good luck to others.