Quantity in Cart

[richardissuchastud]

When users at product_info.php page viewing product info, there's 'Add Qty to Cart:' text box at the bottom of the product page. By default, the quantity is 1.

When users click the add to cart button, they got directed to shopping_cart.php page.

For some reason, the quantity becomes double and multiplied itself by 2. Where should I change the code to reflect the correct amount?

If not, can I turn off that text box in the admin section?