I see tweets, for instance, with special characters in them, that will not display correctly on this system. Here is an example. For numerous of these characters, I see boxes with four characters in them.
彡☆♥彡ＧƠ Ɗ † βԼƐ໓໓ † ᗩறﻉᖇᓮCᗩ彡♥☆彡
I am using Windows XP on this system. I've seen other Windows XP systems that do display them. I don't see my answer coming up in Web searches, etc.