Best algorithm on checking a node in a tree path?

Suppose I have this tree :

           O-ROOT
          /        \
     O-A            O-B
      /          /       \
 O-A1        O-B1        O-B2
 

and I want to do this in C#:

1. Check every node starting from root (I think the best way is trought recursion?);
 2. If I found a node with value = "Hello", return true and STOP the searching function;
 

Can you help me to make the best algorithm for doing it?

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