Web Page displayed HTML instead of plain words in Edit

[Jack T]

Problem:
My co had posted plain words in Edit web pages (Plesk Sitebuilder - create and edit the structure of your site) like About Us, etc but in the Edit Stage it kept showing HTML languages. The URL to log in is http://webxpress.webvis.net/Wizard/Default.aspx .Had made several attempts to rectify but failed.

Puzzle:
How and where to rectify it to plain words. Any one could advise?? Thanks.