Easier one: Go through your linked list, save the previous and the next node and just let the current node point at the previous one:
void LinkedList::reversedLinkedList()
{
if(head == NULL) return;
Node *prev = NULL, *current = NULL, *next = NULL;
current = head;
while(current != NULL){
next = current->next;
current->next = prev;
prev = current;
current = next;
}
// now let the head point at the last node (prev)
head = prev;
}