I am using a Firefox 61.0 browser on a Toshiba laptop running windows 10, and lately have been having problems with this site and a couple others. 

Specifically, on this forum, I am not able to view some of the attachments and links that are posted on various threads.  This is strange because I am able to see some photos and some links but not others.  What is also strange is that all attachments and links work on the Internet Explorer browser.

There are also issues of text overlaying other text in places. 

I am no longer proficient with these things as my meager skill set is over 25 years old now.  I have been through the Firefox toolbox, but can't find anything there that could be causing this problem.  There doesn't seem to be anything in the Windows Control Panel that I can find either.

Is anyone else having this problem?  How did you fix it?

While I'm afraid I can't be of any help with your Firefox/Mozilla issues, except to say I've felt your pain, I can state that after many, many years of being an avid user of the 'Fox, I gave up and deleted it from all devices. It randomly eliminated perfectly 'safe' images and other bits on my lappy and mobile. I could never source the issues and sort out my settings, and no one at Mozilla ever answered my questions, nor were the dedicated forums of any particular assistance. So I went over the ragged cliff edge and am solely using Chrome now. I don't use Edge but occasionally use the ancient IE. I have no dramas using Chrome but I have tightened down what I can on Google's use of my 'private parts'.

TWB, privacy issues has pretty much caused me to avoid anything vaguely related to Google.  I shudder to think what they have in Chrome to spy on me.  It probably isn't any worse than Firefox, but at least I have yet to hear of Mozilla selling my information.

I am using FF 61.0.1 (64-bit) and haven't had any issues with this site or others.
I can see all the pictures without a problem.
Would it be an Anti virus/anti malware or a personal security setup?
As for Chrome, I am like you and avoid it for privacy reasons.

One of these days I need to go through all the stuff on my laptop.  It irks me that when I go to update something like Acrobat it seems to always have something else that gets loaded with it unless I find the decline button.  Just today I seem to have gotten some popup program when I reloaded my FireFox browser.