Not sure what you are doing with part no, but this solves the Msgbox thing

Sub Test()
Dim PartNum As String

Do
PartNum = InputBox("Enter in Part Number:", "Part Number")
If PartNum = "" Then End
myans = MsgBox("The Part Number is: " & PartNum, vbYesNo)

Loop Until myans = vbYes
Worksheets("Sheet1").Range("H10").Value = PartNum

End Sub

best wishes
--
Bernard V Liengme
Microsoft Excel MVP
http://people.stfx.ca/bliengme
remove caps from email

"John" wrote in message
...
I am trying to establish a macro with a message box to loop through until
the
Yes button is pressed. I am using Excel 2003. My code is below:

Sub Test()
Dim PartNum As String

Do
PartNum = InputBox("Enter in Part Number:", "Part Number")
If PartNum = "" Then End
If MsgBox("The Part Number is: " & PartNum, vbYesNo) < vbYes Then
End If
Loop Until vbYesNo = vbYes

Worksheets("Sheet1").Range("H10").Value = PartNum
End Sub