Very strange error running PS 1.5 - no VAT, no product pages

[Inur]

I'm in the process of testing a new release of my website on Prestashop. I  have encountered a very strange error when I thought the testing was done. Tell me what you think.

 

I asked my girlfriend to test the website just like the other people did. So she goes on it and encounters 3 very strange errors nobody has ever seen before.

 

- Prices do not include VAT

 

 

- Product pages are completely empty

 

 

 

 

She uses Windows 8 and the same version of Chrome as I do. I ran the website on an incognito window and in IE and in both cases it works. I have also enabled all the addons she uses in the Incognito browser and this did not affect the correct displaying of product pages or prices.

 

However, in the Chrome Incognito window, Youtube and Vimeo videos which are arranged in product tabs RANDOMLY (not always) appear when the page loads in the top left corner of the screen. Clicking on the correct tab (film) makes the video move back to the tab. Inspecting the website also shifts the video back to where it should be.

 

 

 

 

 

I doubt I'll get any help regarding this but if you have any ideas please let me know. This is rather worrying considering the store is about to go online.

 

 

 

Edit:

 

I have probably found the cause of this error but I'm no IT specialist so I don't understand anything. After logging out, the prices returned to normal and the product page displayed correctly. However, when still logged in, I get this error:

 

 

Anyone?

Edited February 8, 2014 by Inur (see edit history)