products with attributes stock - overselling??

I just found out my stock has gone into the minus numbers, how do I make it stop at zero?? I have added the extra stock numbers for attributes add-on

Check your admin > config > stock > settings

Check stock level  	true  	 
&
Allow Checkout          true

might change allow checkout to false

both are already like that;

Check stock level true
Subtract stock true
Allow Checkout true
Mark product out of stock true
Stock Re-order level 3
Show available stock level in cart when less than order false
Products status in Catalog when out of stock should be set to 0
Show Sold Out Image in place of Add to Cart 1
Product Quantity Decimals 0
Show Shopping Cart - Delete Checkboxes or Delete Button 3
Show Shopping Cart - Update Cart Button Location 3
Show New Products on empty Shopping Cart Page 1
Show Featured Products on empty Shopping Cart Page 2
Show Special Products on empty Shopping Cart Page 3
Show Upcoming Products on empty Shopping Cart Page 4
Show Notice of Combining Shopping Cart on Login 1

Did you read my post?

Change this:

Allow Checkout false

ah thanks