Hey, i had a fresh install of windows 8.1 on my PC and i have installed the fonts i backed up from my previous system,
including some other fonts i downloaded from various sources.

After i did that some of the fonts in my Windows were ruined (The system fonts looked different or didn't show at all) and some other fonts in different web sites were changed and looked weird, for example the fonts in Facebook and another example is the fonts in themeforest.net

I even couldn't remove all the fonts in my fonts folder and install a pack of default windows 8 fonts i downloaded to fix the problem so i had to format my system all over again.

Is there a way to install fonts with no danger of this to occur again?

Thanks!

as long as we don't have any idea of the "fonts you downloaded from various sources" it might be difficult to know if this will occur again.
no idea about the fonts, no idea about the various sources.
and what about the Windows 8.1 ? genuine ?

Everything is genuine and the fonts were partly purchased and partly free fonts I downloaded for personal use.

when ? before ttf and otf ?
where ?
what ?
previous OS on which they worked ?

it's borinng to have to drag it out of you...

I understand that but all I did was to install fonts I had backed up on a fresh install of Windows, it would be much easier if you could tell me how to avoid it and which fonts could create this problem, like which fonts the sites is stated above are using.

Thanks.

ok.
more than 100.000 fonts on earth, and billions of "various sources" where you can download crap.

i pass my turn, good luck.

I am amazed you picked it up - it probably never ever installed the fonts. One of those "I know better and no-one tells me what to do and how" thingies.

There's no reason to assume stuff and reply in this manner,
If you can't help it's fine, You guys probably know much better than me, and that's why i'm here asking my question.

I understand i might have given low amount of information but that's all i know, if you could just help me by directing me to the right question to ask it would be helpful.

Anyway i'll ask it in another way, what fonts does http://themeforest.net/ use in the top menu, it was the first thing i noticed that changed.