You need to remove the second node and add it again from the setup, follow the instructions from http://msdn.microsoft.com/en-us/library/ms191545(SQL.90).aspx
Actually there is an article where are the steps to follow for the scenario that you described
http://msdn.microsoft.com/en-us/library/ms189117(SQL.90).aspx (Recovering from Failover Cluster Failure)
http://msdn.microsoft.com/en-us/library/ms181075(SQL.90).aspx (How to: Recover from Failover Cluster Failure in Scenario 1)