|Where are you displaying the text and seeing the boxes? To the console? To a TextBox or TextBlock?
If they are going to the console, then it probably makes sense that you'd see boxes as the console font is probably not set properly to a font with those characters. Use the system menu to change the font to a unicode font and try again if that's the case.
If it's to a textbox, again, check the typeface you're using. The browser is probably dynamically loading the font glyphs it needs and painting with those.