I'm having trouble with my query.

Code:
SELECT tblItems.title, tblItems.imagepath, COUNT(*) as count
FROM tblItems, bought, bought as alsobought 
WHERE bought.ISBN = ' & ISBN & ' 
AND alsobought.ISBN != bought.ISBN 
AND tblItems.ISBN = alsobought.ISBN 
GROUP BY tblItems.ISBN HAVING count > 1 
ORDER BY count DESC 
LIMIT 4;
my tables are as follows:
tblItems has info about the book - ISBN being the Primary Key, title, author, etc.

bought has two columns, one for the transaction number (id) and one for the item that was purchased (ISBN). This table looks like this
1,1234567890123
1,9876543210987
1,0879543569842
2,8544468046023
2,8800097856128
etc

You know how amazon gives you suggestions when you look at an item based on how many other ppl bought that item as well as another item? That's what I'm trying to achieve. Unfortunately my count field is giving me extremely high numbers - higher than the total number of rows in my tables.

Can anyone tell what I'm doing wrong?