Checkbox w/ Date Stamp

[YamiMarik777]

I have a main form that has Vendor Number and Vendor Name. Then I created a subform that has the invoices attached to that particular vendor. I did create a checkbox labeled Paid. When a user puts a checkbox in I want Access to put Today's Date in the DatePaid field in the invoice. Another problems is when in the Invoice subform, when a user clicks on the Paid box, it puts a check in all boxes. How do you tell Access that to check to particular box that is clicked on?

Any Help would be greatly appreciated. Thank you.