title: How to add new string to Registry Entry of type REG_MULTI_SZ?
body: <p>I have 1 registry entry of type REG_MULTI_SZ. This entry already contains some string in it.</p>
  
  <p>Now i want to add 1 more string to it by using .net class<code>RegistryKey</code> . this class has method <code>key.SetValue(string,string)</code>. But when i use this method it removes all strings which are already there and then inserts new string, in short it overwrites. 
  I don't want to touch strings which are already there, just want to add new string at the end.
  Anybody know how can we do this in C#.</p>