Lost Product Pages - Categories are Fine

I was informed by my host to upgrade to the latest version of Zen Cart, as they were installing the latest ver of PHP and that would break out Cart. We were running 1.3.8 now latest 1.3.9g.

I did this, I followed the instructions, and after a bit of trial and error I have got 2 of our sites back up and running.

The problem I have is that all my categories are there with the products showing in the lists, but when I click on a product it takes me to a blank page. Ie nothing shows up.

I searched the forum and found that this is probably something to do with - tpl_product_info_display.php - But im not sure I did any editing of this as my backup files of the old version doesnt have this file in my template overrides.

The site link - http://www.belltent.co.uk/index.php

Please can someone help me with this, we run 2 sites but have not put the multi-site module on it yet as I want to see one working fine before setting up the second.

Thanks in advance.

If you are running v1.3.9 ... check the /cache directory and see if you see any debug log files when you click on a Product and get the blank display ...

Chrck similar threads at the bottom of this post and
https://www.zen-cart.com/tutorials/index.php?article=82

@Ajeh - Wow your a legend, thanks for the help, the problem was I had forgot to upload Zen Lightbox Addon, once that was inplace we have product pages again.

@Kobra, thanks for that link too, I did not find it when I was looking, diddnt think to look in the FAQ's.

Again thanks to you both, I think the community would grind to a halt without your exhaustive efforts helping us all.