Given that it calculated correctly when you first entered the formula this is
a longshot but try:-

Tools|Options|calculation and make sure it's set to automatic.

Mike

"Susie" wrote:

I have typed a value (1500) into cell A5. I have typed a simple formula in
another cell (B5). The formula was =A5*2. When I then changed the value in
A5 to 1000 the value in B5 didn't change. Why is this? I have just started
using Vista and used to do a lot of formulas before and never had this
problem. How do I solve it?