My edge and IE are displaying text as times new roman when they are supposed to render Arial or Sans-Serif according to CSS.
The default font for Sans-Serif is set to Calibri. Manually editing the CSS to replace arial with calibri works however.
Ok now after installing Office 2016 my laptop showed the same symptoms, but was fixable downloading the provided Arial Files here.
Thanks a lot!
However as mentioned before my original Problem was not so easily fixed.
Some program registered a second fonts folder (how do you manage that I want to delete it?) that kept overwriting the Arial Fonts on every Reboot. I had to delete/rename the fonts in there and once again reinstall the proper Arial Fonts again and it worked (finally!)