using System;

using System.Xml;

public class Program

{   

    public static void Main()

    {

        var raw = @"<Drive>

    <Data0 Key=""1"" Name=""AA"" />

    <Data1 Key=""2"" Name=""BB"" />

    <Data2 Key=""4"" Name=""CC"" />

    <Data3 Key=""10"" Name=""WW"" />

    <Data4 Key=""11"" Name=""WE"" />

    <Data5 Key=""12"" Name=""VW"" />

</Drive>";

        XmlDocument doc = new XmlDocument();

        doc.LoadXml(raw);

        var result = doc.SelectNodes("//*[starts-with(@Key, '1')]");

        foreach(XmlNode r in result)

        {

            Console.WriteLine(r.OuterXml);

        }

    }

}