Weight Loss Formula In Excel

I need some help with excel formluas?

I have a spreadsheet that adds up weekly weight loss. when i add my new weight it in stones it converts to pounds. another cell then has a formula that works out weekly weight loss in pounds. when i enter this weeks data it adds up next weeks weight loss as starting weight – 0! How can I get these cells to say 0 until the new data is entered??
Eg =(0 until c1+c2 is entered)

I will skip the conversion from stones to pounds. You already have this. I will use th Excel cell numbers on my spreadsheet, you change to suit your spread sheet.
1) In Row 4: In each cell enter your weekly weight in stones.
D4 week 1 , E4 week 2 F4 week3 etc etc.
2) this is auto converted to pounds in cells D5, E5,F5 etc. Remaining cells are empty, waiting for following weeks’ entries.
C) Imagine you have 178 in cell D5 and you then have 176 in cell E5. You want the weight loss, 2 , to be shown in cell D6
D) In cell D6 enter exactly: =IF(E5>1,D5-E5,”0″) press enter. Pay attention to all the commas, brackets, ” ” etc. The “0″ is zero not capital O
E) Cell D6 will show 2.
F) Highlight cell D6, drag the formula all along row 6 using the small black square on the bottom right hand corner of the highlight box. I am sure that you already know how to do this.
G) When next week you enter the new weight, and have 173 in cell F5, cell E6 will show 3. and so on.
H) Weight Gain is shown as a negative number.
I) Now you have a weekly tabulation of your weight loss in row 6. But you want an additive weight loss so that you can see at a glance how much weight you have lost from the beginning.
J) Do this in Row 7. In D7 enter: =D6 press enter. In cell E7 enter E6+D7 and press enter, Highlight E7 and once again drag all along row 7 to enter formula in whole row. Do not highlight and drag D7. This last row will give you the total weight loss since starting. It accomodates any week’s weight gain and if by mischange your weight goes above your original starting weight, it will give a negative result.
K) If you know how, I would protect all the rows except where you enter your original weight.

If you have a problem, Email me and I will send you the ready to use spread sheet
Trying to describe setting up a spreadsheet in this solely written format is not easy.
I have double checked this by making my own sheet according to the directions, but here’s hoping it works for you.