I suspect that your reinstall of Outlook 2003 created a new mail profile
that does not know about your old PST file.  Enabling viewing hidden files
and folders.  Then with Outlook closed, open the Mail applet in Control
Panel and click the "Show Profiles" button.  Click Properties, then the Data
Files button.  Click Add and the browser window should open
"%UserProfile%\Local Settings\Application Data\Microsoft\Outlook".  You
should see one or more PST files there.  One will be the one in the current
profile and the other should be the one you had been using before the
reinstall.  Select that second one and click OK.  This should add it to the
current profile.  Click OK or CLose until you are back at the Mail Setup
window.  Click the E-mail Accounts button, then Next.  In the "Deliver new
e-mail to the following location" drop-down at the lower left, select the
PST you just added and click Finish, then Close, then OK.  You should be out
of the Mail applet now.  Close Control Panel and start Outlook.  Does it
seem more correct now?