helenxmas on "My Wordpress site is missing and damaged"

I created a new wordpress site in a folder (sub directory) and we have just moved to the contents to the top level directory.
The whole site is now malfunctioning.
Nothing is showing and I cannot even install the theme I was using.
The pages appear to be there, but won't display - something has gone horribly wrong and I desperately need help. Can any one advise me?
http://www.bognor-local-history.co.uk/