Yes.
unless..... some unscrupulous character has inserted a "before save" macro into your worksheet which you are unaware of ...
ie
<PRE>
Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
Range("A1").Value = 999999
End Sub
</PRE>
which, although having no value whatsoever other than to screw you up, would make the cell A1 equal to 999,999 before you saved your worksheet
I'd go with Von Pookie's answer though, unless you have some psychopath in your office......
Hope this helps,
Chris