Help with inserting symbols in office 2004

[newtomacs2007]

Hi, all the Greek symbols in my manuscript have changed to "empty boxes". Also, when I try inserting them back in via the "insert" and "symbol" option, the text also turns up as empty boxes. Any ideas on why this happened? All the symbols in my files were fine before.

I just read online about the better "character palette" option and it works, but is there some quick fix that can change all the "empty boxes" back to the Greek symbols?

Thanks for your help!