need some help with quanity

[hootienchyna]

i am not sure what i need to do here, i had an item that i had 1 left out of 2 and when someone went and put in a qty2 to buy i now have -1 in stock which i do not want. when an item runs out i want it to end at the qty of 0.
thank you
here is my settings:

Products Quantity Box Shows: Yes, Show Quantity Box No, Do not show Quantity Box
Product Qty Minimum: 1
Product Qty Maximum: 0 = Unlimited, 1 = No Qty Boxes
Product Qty Units: 1
Product Qty Min/Unit Mix: Yes No
Products Description:

Products Quantity: 1

[stevesh]

Look in Admin - Configuration - Stock