read a string from a web page

Hello everyone,
I am working on an asp.net project (visual studio 2005 using C#).
I need to read a string posted on that page.
For example:
http://www.mysite.com/page1.aspx.
I need to check if this page contains the string "successful operation" or "Unsuccessfull operation". This page contains no controls or component (nothing, just one of the 2 messages displayed above).
how can I do that?
Thank you.
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