Have you downloaded any fonts using TypeKit?
Check your fonts. You probably have one that is corrupt.
i had.. and if i look up Windows>Fonts, then what should i do next?
i've deleted the Fonts i've recently downloaded and installed, and there are leftovers..
at this time, what should i do?
so this time, i deleted a lot of fonts, including "Myraid Pro", and it worked.
but how can i download or install any other Fonts in safe way?
Most fonts are fine. I say just work as normal until you run into a problem (rare). If you do, remove the offending font and carry on.