Browser can't find local help files

I have installed LO 6.4 which works (other problem asked separately). I have installed and removed English (UK) pack several times but every time I try help in Calc or Writer I get the following message:

Firefox can’t find the file at /C:/Program Files (x86)/LibreOffice/help/index.html?Target=scalc/.uno:HelpIndex&Language=en-GB&System=WIN&Version=6.4.

The LO help folder has En-GB and Media folders. There is no index file or folder at that or lower levels.
Any Ideas please.

Frequently asked questions - General - The Document Foundation Wiki - check if your help pack and your LO are of the same architecture (32- or 64-bit both).

Both are 64 bit.

In the LibreOffice folder there are:

Folders: help presets program readmes share


What else can I try or can I provide.more info?

Then it’s absolutely unexpected that it looks something under Program Files (x86). Both must had been under Program Files. You might need to remove all LO help packs from the system, and then re-install anew … or even LibreOffice itself.

I uninstalled both Libre Office and the help pack and then reinstalled. This time both were installed in Program Files/LibreOffice and not Program Files 86 as last time. I’ve no idea how they ended up in 86. But it all works now. Thank you for your help.