Outlook 2002 Spell check not working properly

[moonpig]

A client of mine is using Outlook 2002 with Word 2002 as the email editor. When replying to emails with HTML formatting any misspelled words will be underlined in red as usual. When replying to a Plain Text email no spell checking is performed. Even deliberatly misspelled words will be ignored both during typing and when running a spell check.
There is no error message, it just says spell check is complete.
This is now also happening in Word. Misspelled words are ignored and spell check says its complete.

I have checked the usual:

Word 2002
Under Tools/Options/Spelling & Grammer - Check Spelling as you type is selected, Hide spelling errors in this document is unchecked, always suggest corrections is checked.

Outlook 2002
Under Tools/Options/Spelling - Always suggest replacements for misspelled words is selected.

I would gladly welcome any suggestions. Thanks