Windows 7 PC running Microsoft Excel 2003. Documents are not Saved to network when doing a save, only saves locally. BUT does when doing a "Save as" I rename the document to the network. Can anyone help me?

Windows 7 PC  running Microsoft Excel 2003.  Documents are not Saved to network when doing a "save" , it only saves locally. BUT does when doing a "Save as", THEN  I rename the document and only then can it be seen on the  network.  Then I have to go back and delete the 1st document to keep chaos from starting.  What the heck????     Can anyone help me?