Excel VBA Find/Replace Macro - excel

Question

Good Morning,
I am working with a rather large dataset and I am attempting to Find/Replace values which have been modified in one spreadsheet back into the original. What I would like to do is have the macro look for the information in Cell A1 and Replace it with the value in Cell B1, and then continue down until Cell A3600:B3600. Generally, I'm pretty good at peicemealing the code I find on here to get it to do what I want, but I'm at a loss as to what I should be looking for.
What I have right now is:
Sub Macro1()
'
' Macro1 Macro
'
'
Range("A1").Select
Selection.Copy
Cells.Replace What:=ActiveCell.Value, Replacement:="????", LookAt:=xlPart, _
SearchOrder:=xlByRows, MatchCase:=False, SearchFormat:=False, _
ReplaceFormat:=False
End Sub
From here I am at a loss. I understand Range("A1").Select will paste into the Find section of the Find/Replace box, but how do I tell excel I want to select another Cell, in this case B1, for the replace portion? And then how do I tell Excel I want it to keep doing this until it runs out of values in the A Column?
Thank you in advance for any assistance you can provide.

Answer 1

I think you are after something like the code below:
Option Explicit
Sub Macro1()
Dim Rng As Range
Dim OrigStr As String, ReplaceStr As String
Set Rng = Range("A1:B3600")
OrigStr = Range("A1").Value2
ReplaceStr = Range("B1").Value2
' option 1: replace only if the whole cell's string equals to OrigStr
Rng.Replace What:=OrigStr, Replacement:=ReplaceStr, LookAt:=xlWhole
' option 2: replace also partial match inside the cell's string
Rng.Replace What:=OrigStr, Replacement:=ReplaceStr, LookAt:=xlPart
End Sub