DeleteLast Function of a SinglyLinkedLast

I can't figure out how to fix this. I'm trying to move the pointer all the way to the end of the list but it won't even run. It builds fine, no compiler errors, just doesn't run. It freezes execution.

Code:

		void SinglyLinkedList::DeleteLast( ){

			Node* newNode1 = new Node;
			Node* newNode2 = new Node;
			Node* deleteNode = new Node;

			newNode1 = first;

			if(Length() == 0)
				cout << "List is empty." << endl;

			else if(Length() == 1)
				DeleteFirst();

			else
				while(newNode1->next != NULL || newNode2->next != NULL){
					newNode2->next = newNode1->next;
					newNode1->next = newNode2->next;
				}

				if (newNode1 == NULL){
					deleteNode = newNode1;
					newNode2->next = NULL;
					delete deleteNode;
					}
				else
					deleteNode = newNode2;
					newNode1->next = NULL;
					delete deleteNode;

Well you shouldn't be calling new at all, you're trying to delete a node, not create three more!

Then it is

Code:

while ( temp->next ) {
  prev = temp;
  temp = temp->next;
}
// here, temp is the node to be deleted
// prev is the node before it (you want to set prev->next to NULL)