It appears that from very beginning you were using improper coding set, so now it would be a hard job to restore all of it. As always I would recommend
Notepad2 program which could help you for large files.
I know on many hosting servers there are internal problems with the standard mySQL encoding settings. For example if you run the following statement:
SHOW VARIABLES WHERE variable_name LIKE '%character_set_%';
(or for older mySQL versions it could be like this:
SHOW VARIABLES LIKE '%character_set_%';
)
you must be sure that
character_set_server and other same kind variables are set for the same encoding. If some of them differs, this usually causes wrong posting of the characters into DB and displaying them later.
For foreign language symbols I would always recommend to
set up the forums in UTF-8 mode. Having UTF-8 you will most likely avoid future problems with such symbols.