Segmentation Fault using linked list insertion sort

Question

I've been working on this project for a while now and it's completely done. Except that when I run it in Linux I get a segmentation fault. I'm a beginner with C++, and while I understand that a segmentation fault has to do with trying to access already freed memory, I don't understand where I'm going wrong with the memory I am trying to access. Below is the function where I am having the problem. I marked the line of code that I think is causing the problem with a comment. Please let me know if you see what I am doing wrong, I'd really appreciate it!

int TsuPod::SortSongList(string x, string y, int z)
{
    Song InsertSong(x, y, z); //creates song object

    node* newNode = new node; //creates new node

    //initializes all the node's values
    newNode->title = InsertSong.GetTitle();
    newNode->artist = InsertSong.GetArtist();
    newNode->size = InsertSong.GetSize();

    //case 1 - Inserting into an empty list
    if(head == NULL)
    {
        head = newNode;
    }
    else
    {
        curr = head;
    prev = NULL;

    //Traverse
    while(curr != NULL)
    {
            if(curr->title >= newNode->title)
        {
            break;
        }
        else
        {
            prev = curr;
            curr = curr->next;
        }
        }
    }   

    if(curr == head)
    {
    //case 2 - Insert at head
    newNode->next = head;
    head = newNode;       //Causing Segmentation fault?
    }
    else
    {
    //case 3 - Insert after the head
    newNode->next = curr;
    prev->next = newNode;
    }

    remainingMem = remainingMem - newNode->size;
    slots++;
    return 1;
}

Answer 1

The first thing that hits me in the eye is the following:

if(head == NULL)     <--- lets assume that head was null
{
    head = newNode;  <---- executed
}

else
{                    <---- not executed, skipped
    curr = head;     <---- this is skipped, curr is not assigned to head
    prev = NULL;

    //Traverse
    while(curr != NULL) { ... }
}  

if(curr == head)    <----- Huh... What is curr right now? When was 
                           curr last set to a value 
{ ... }

I'm not saying that segmentation fault is caused by this, I'm just saying that this piece of code is fishy.