Grouping
Radio buttons must be grouped on a form, for instance inside a group box or Panel
Usage
MyRadioButton.Checked = true;
MyRadioButton.Checked = false;
if(!MyRadioButton.Checked) //If not checked
Feel free to comment if you can add help to this page or point out issues and solutions you have found. I do not provide support on this site, if you need help with a problem head over to stack overflow.