Question Font on all browsers affected

[SirAchesis]

So the font on all of my browsers has been changed to a really bad one.
The font seems to only affect:

1. Markdown text
2. Certain elements of it

Here is an example picture in markdown.
(Using Jupyter notebook on chrome)

As you can see headings and bold are affected the worst here.
Any ideas on what is causing this?

I've tried resetting font seetings and running this reg. file

But nothing has solved the issue so far.

 

[rgd1101]

what other browser did you use?
only on some site or any?

 

[SirAchesis]

what other browser did you use?
only on some site or any?

I tested it on IE, Edge, Firefox and chrome.
Affects all websites(Only markdown though)