Webclient doesn't support frames

Hello people! This is my first post here. I am currently developing an application that is supposed to get data from a website, get some product information, then place it in a database etc.

I am using webclient but the url I want to retrieve from only returns part of the page and with the message "your browser does not support frames".

How can I get the "full" page downloaded so I can parse the html(string) using my RegEx expressions? In other words get the same html as I get when I manually use the right-click and view source on the url?

I will paste some info below. Thanks in advance for all help.

WebClient fileReader = new WebClient();
fileReader.Credentials = credentialCache.DefaultCredentials;
fileReader.Headers.Add("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705;)");
Stream data = fileReader.OpenRead(url);
StreamReader sr = new StreamReader(data);
string html = sr.ReadToEnd();
infoTextBox.AppendText(html);