Cannot create customer account even after fresh installation

Hi, I have been looking up down left and right through as many sites as possible but have been unsuccessful in finding a solution to my delimma. If there is some other thread or post I have missed please let me know I would be so appreciative.

My Host is siteground.com. I have Zen cart 1.3.9h. I had installed a template and added a number of modules such as easy populate, SEO Urls, Currency updater.

I couldn't however after trying today manage to register in my site as a customer. After trying to create an account, I just get returned to the same 'create account' page as though I hadn't entered any information in at all! I have seen this same kind of error in other forums and had thus tried to follow instructions such as readding all the create_account files in -
**includes/modules/pages/
includes/default_template/templates/
includes/languages/english/
**
However this didn't work.

I then tried to go back to my original default template incase there were corrupted files in my template folder as I read in another thread. No luck. Same problem.

I then finally decided to back up my site and reinstall Zencart from scratch. No improvement.

I am all fresh out of ideas from that point and have absolutely no idea how even after a fresh installation I still wouldn't be able to add customers. Any advice would be greatly appreciated.
Kind regards, :blink:

You did not specify the server OS
or the versions for the mysql, php, apache etc