opening a file of an ol version does not show formulae

I Have a document fro an old, old version 3.0 or may be earlyer (1998).

I open the file with the 9.5.1. , 30 day trial version, OK but the formulae incorporated into the text do not appear.

There are some fonts used in the old versio missing in my computer now.

IThe formulae do not appear using the  prefernces of quark neither using the specification of the original document.

Can I do something about it?

How can I solve the problem?

THANK YOU

Camilo