In Excel 2000 I am using the following to get data from another sheet. Also I
am using it in other cases to get data from another workbook but the issue is
the same.

=VLOOKUP(A2,'BV data'!A:B,2,FALSE)

This returns '#N/A'. Clearly it is not finding a value. If however, I go to
the source cell (key) and press F2 to edit the cell and then press return
without making ANY changes, the formula works! With a lot of data this is a
completely impractical workaround.

Changing the format to number, cutting and pasting as values... all of this
doesn't work. It's not a precision issue as turning on the 'as displayed'
function on the Calculation tab under options doesn't help.

It's as if the number is appearing in the cell but its not really
reginstered there as far as Excel is concerned.

Really causing problems. Would really appreciate any help. Thanks in advance.

Colin