when typing in outlook 2010, pressing enter changes the text to a (heading)....

hi

i have a user here, who's running office 2010.

in outlook, when she starts a new mail,  types the text, then presses enter twice, the formatting of the text is change automatically from Ariel, to  calibri (heading)

this doesn't happen every time, but it does happen a lot. 

also, when the text is changed, you cant check its spelling, IE spell checker ignores the text, even if its blatantly wrong.

I've tired a few things. 

• changing styles
• renaming normal.dotm file
• Re-did her signature.

but nothing has worked.

any suggestions ???