I am trying to enter numerical data into Excel2002. It worked just fine this
morning, but now if I try to enter a number into a cell, the workbook jumps
to another cell instead.

For example, if I want to type -30 into cell B6, instead of showing what I
have typed in cell B6 I suddenly find myself in cell B36. Trying to type in
dates has an even more random effect, but typing in text seems fine.

I have tried typing the numbers directly into the text entry box at the top
instead of into the cell, but that still has the same effect.

I'd be really grateful if someone can suggest what to do to make it stop as
I can't enter any numerical data until I sort this out!

Many thanks.