I need to search for a particular string in a very large spreadsheet, and
when I find it I need to replace it with the contents of, or a reference to,
the cell 3 to the right and 2 above it.

For example... Let's say the string is 'XXXX'. Lets say the 1st instance of
'XXXX' is in B10 and the 2nd is in B24. So what I want is for B10 to equal
"=E8" (or the contents of E8) and B24 to equal "=E22" (or the contents of
E22).

This is for a one off manipulation of a large file (a1:bg56856). Any
ideas...?