我用texmaker+miktex2.9，開很久以前編的檔案時，出現
==============================================================================
It seems that this file cannot be correctly decoded with the default encoding
setting (UTF-8)
Use this encoding:
=============================================================================
它有一個選單給我選
可我不知以前的編碼是什麼？我試過UTF-8、Big5。中文顯示都亂碼。
我確定不是字型的問題。請問如何查編碼？