Cannot find Outlook .pst file in Outlook 2003/2007

Hi Experts,
I have got a problem regarding to my inability to find .pst file in Outlook 2003/2007.
I downloaded repair tool to repair .pst file and tried to find it but no .pst file was available.
I used normal path to find the pst file (Documents and Settings/username/application data/microsoft/outlook), then went through Outlook2003- Tools-Options-Mail Setup tab- Data File, done search, selected ''Show hidden files and folders'' in Windows Explore and no .pst file is coming up.
Any clue where else to look for it so I can try to repair it.
Environment: Outlook 2003/2007 and Exchange 2007

Thank you in advanced!