Help my Arial has gone italic!!?

[invalid entries]

About 3 weeks ago the text on my compter (XP with Office XP) went italic. I tracked it down to the Arial font. It happens whenever that font apperas, on web pages, documents, in Front Page. Only that font, no other. What have I done and how do I undo it.
Thanks

[Ronbmy]

During installation of some software the arial font is changed to italic. If the installation is not completed the font stays as italic.

Run a search through the Micro$oft Knowledge base.