string strremove = "Text to remove";
string stremovedtext = strremove.Remove(1, 3);
MessageBox.Show(stremovedtext);

//to find a text with in a text
string strfind="Text with in myself will  be searched";
if (stremovedtext.Contains("will") == true)
{
MessageBox.Show("String found");
}
else
{
MessageBox.Show("String not found");
}

string strstartsorends="Text with in myself will  be searched";
if ((strstartsorends.StartsWith("text")) || (strstartsorends.EndsWith("text")))
{
MessageBox.Show("It is started or ended with text");
}
else
{
MessageBox.Show("It is not started or ended with text");
}