Safe Site to Download Ability for Computer to Read Chinese Characters

I do hope that this is the correct topic area where I should be asking something like this.

Whenever I go to a site, or even on this site, where Chinese characters are displayed as a font(?), my present computer is unable to display them. I just get those little boxes instead of the characters. Where is a safe site to download the ability for my computer to be able to display them?

On other sites than this one, I do get the little box that appears asking me whether or not I want to download something in order to have them displayed. However, I don't know the origin of that box or whether I should trust downloading anything via it or not.

Thanks!