Problem opening file in XP

HTML & CSS
1

I made a newsletter template for a client, but when she open it in a text editor some character, like quotation marks’ are converted to what looks like hex code.
It open fine on Mac and Vista. She is using XP. Any ideas how to deal with this issue?

Thanks E

2

It’s probably character encoding issues maybe it’s a UTF-8 file or something with weird encoding and is being edited in a tool that doesn’t have proper support, etc.

3

Is there a better format to use other than UTF-8? According to a reference I found, XP uses Unicode-standard by default. The text editor I uses has options for:
UTF-8
UTF-16
Western-ISO
And a few foreign languages.