How can I tell macro to perform operations below "= vbNo Then" ?

Thank you, Your code ran perfectly. One final question: Why do I get and "Else" Compile error when I place the following code just above your last "Else":

Sub OPTIMIZE()

a = MsgBox("OPTIMIZE AWSORT FOR A MINIMUM OF TWENTY-FOUR INSTRUMENTS. HAVE YOU COMPLETED OPTIMIZATION?", vbQuestion + vbYesNoCancel, "HonorSystem24")

If a = vbYes Then
Call Combo_MacroLessThan4k

ElseIf a = vbNo Then

ActiveWindow.ScrollRow = 624
Range("V13:V14").Select
Selection.Copy
Range("V640:V641").Select
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Range("W13:W14").Select
Selection.Copy
Range("W640:W641").Select
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Range("X13:X14").Select
Selection.Copy
Range("X640:X641").Select
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Range("Y13:Y14").Select
Selection.Copy
Range("Y640:Y641").Select
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Range("Z13:Z14").Select
Selection.Copy
Range("Z640:Z641").Select
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Range("AA13:AA14").Select
Selection.Copy
Range("AA640:AA641").Select
Selection.PasteSpecial Paste:=xlPasteValues, Operation:=xlNone, SkipBlanks _
:=False, Transpose:=False
Range("V13:Z14").Select
Selection.ClearContents

Application.Calculation = xlAutomatic

ActiveSheet.Range("$BB$21:$BD$629").AutoFilter Field:=1

ActiveWorkbook.Worksheets("Sheet1").Sort.SortFields.CLEAR
ActiveWorkbook.Worksheets("Sheet1").Sort.SortFields.Add2 Key:=Range( _
"aw30:aw629"), SortOn:=xlSortOnValues, Order:=xlDescending, DataOption:= _
xlSortNormal
With ActiveWorkbook.Worksheets("Sheet1").Sort
.SetRange Range("B30:BA629")
.Header = xlGuess
.MatchCase = False
.Orientation = xlTopToBottom
.SortMethod = xlPinYin
.Apply

Else
Exit Sub
End If
End Sub

Excel_World_Champion