Use this function to do a search and replace function. It works by finding the next instance of the string that you are looking for, and gets everything to the left and right of it, inserting the new string between the two parts.

Public Function replaceall(searchstring As String, _
findstring As String, replacestring As String) As String

Dim curpos As Long

curpos = 1

Do

curpos = InStr(curpos, searchstring, findstring)
searchstring = Left$(searchstring, curpos - 1) & _
replacestring & Right$(searchstring, Len(searchstring) _
- curpos - Len(findstring) + 1)

Loop Until InStr(searchstring, findstring) = 0

replaceall = searchstring

End Function

You could easily modify this function to search only a certain range of the string, if you needed to.