I have never run into anything like this,
I looked into excels help on programming find and replace functionality,
they offer the following code:
With Worksheets(1).Range("a1:a500")
Set c = .Find(2, lookin:=xlValues)
If Not c Is Nothing Then
firstAddress = c.Address
Do
c.Value = 5
Set c = .FindNext(c)
Loop While Not c Is Nothing And c.Address < firstAddress
End If
End With

I put a couple 2's in column a and ran and everything was fine. Went to work
with thoughts of how to put this to use in my head and when I got home needed
to type up a spreadsheet for work. Now whenever I typed a 2 it changed to a
5, I threw away the old Excel spreadsheet earlier and deleted it. Any clue on
how to stop this would be greatly appreciated.

-John