I would like to display a date where the value of another cell is 0.

I have created a very basic spreadsheet to calculate mortgage repayments and work out repayment date based on payments made. eg...

Cell A2 = the date
Cell B2 = starting balance for that day
Cell C2 = any interest for that day
Cell D2 = any payments for that day
Cell E2 = closing balance for that day (B2+C2-D2)
Cell A3 = E2 and the process above is replicated for 800 rows

I would like to achieve 2 things:

firstly stop the calculations once the figure in column e = 0 and the amount has been paid off
Secondly I would like the date corresponding to the date the balance in column E = 0 to be displayed in Cell A1

Really appreciate your help