Browser was being slow, so I reset it. Since then, some pages don't load properly, pages have a plain white background and plain black text in a list. Also..
..some secure pages won't load. Some will load after you grant a security exception, but some say you cannot give this page a security exception because something to do with HTPS I've forgotten the exact words. Some of these pages I know are secure, like outlook, or Al Jazeera. Even the Mozilla Support page won't load properly and I had to ask this question using a different browser it's white background, with plain black text and hyperlinks are in blue. The text is in Times New Roman (don't know if that is an important detail). Some pages don't finish loading, like Facebook has all the right colours but the images won't load and there is text in place of the picture (I assume the text is the image's caption). I already tried uninstalling and reinstalling.
Alle svar (1)
When you use the Refresh feature, Firefox moves your old settings files to the desktop, inside a folder named Old Firefox Data. Please hang onto that in case we need it.
When you get connection errors for nearly all secure sites after a Refresh, the problem usually is Firefox losing trust in your security software that intercepts and filters secure connections. Products with this feature include Avast, BitDefender, Bullguard, ESET / nod32, and Kaspersky; AVG LinkScanner / SurfShield can cause this error on search sites. The same issue can arise with parental control software such as Microsoft Family Safety.
If you have any of these products: This support article will walk you through checking for this problem: How to troubleshoot security error codes on secure websites.
Otherwise, Firefox might have lost trust in some malware on your system, so we'll suggest next steps to investigate if the above isn't the explanation.