I have a c# asp.net 3.5 app I am trying to open a window from code behind after a certain event. I have this but its not working and there are no errors in firebug
Assuming that the pre-conditions are true. You need to pass an additional parameter to the RegisterClientStartupScript method call to indicate that scriptTags need to be added.
Page.ClientScript.RegisterStartupScript(this.GetType(), "openCredentials", string.Format("radopen('Services.aspx?clientId={0}, Window_Services')", openCredentialsWindow_ClientId.ToString()),true);