Webpages on Safari are showing text only

Hi Everyone,

Having a bit of trouble with my internet browsers on MacBook Pro (Running Yosemite 10.10.5/Safari 9.0.1)

I have Safari and Google Chrome installed on laptop and experiencing problems with both.

On Chrome, when trying to open most webpages I receive an error saying that my connection is not private.

Whenever I try to open any webpage on Safari, I'm met with an invalid certificate warning. I can usually click on continue and this will bring me to the desired page but this will then lead to the next problem...

The vast majority of pages I can open are text only (on safari and Chrome)

I'm not sure if these issue are related or not, I just think it's interesting that I'm encountering the exact same problem on both browsers.

I've already tried a few things:

- my date and time settings are correct, have been reset multiple times and are now back on automatic

- I've cleared caches and history again and again. Reset Safari and Chrome multiple times

- Run CCleaner on the laptop twice to make sure both browsers were completely clear

- I had avast antivirus on the laptop and read that disabling the web shield might fix the problem... it didn't... I then deleted avast to see if it would help... which it didn't

- I have images, styles and JavaScript all enabled in Develop menu

- I don't have any extensions installed at all on either browser

- I've tried reinstalling the OS but am either told that the verification of my laptop has timed out or that there aren't any for my particular laptop. I assume these error messages are appearing for the same reason that I keep getting invalid certificate warnings, as I've previously reinstalled the OS and everything went fine.

(Safari works fine in guest sessions on the laptop)