Automated testing to check a webpage on a site is displayed?

Question

I'm doing a small project and just wondered if someone could give me a little help as were to start because my programming experience is only at a basic level really. The project is to write a c# application with Selenium that can be executed from the command line. When executed the application will then log into a website and check that every webpage can be opened on the site without displaying a server error. By checking the webpage displays correctly somehow or by simply taking a screen shot that can be checked after woods for any server errors. The application needs to be run against different websites, so the webpages really need to be stored in an external document such as a text file. My main question is can this be done and if it can how would you go about it. Also, as the application needs to be run against different websites. How will the application know how to get to the page itself. I am really looking for some guidance and a starting point. I would really appreciate some help on this or just some guidance to help me get started.