Outlook Problem

I am using Win Xp with Service pack 2 installed.
Now whenever I open my Microsoft outlook,outlook is hanging,I tried the repair and detuct option,repiring the office installation but no use But using same pst I can import mails to another system and I can work.My pst size is 750MB
I used Scan pst tool to check any error in my pst,there is no error found,I reinstalled the ofice in different drive but still my problem is persisting,suggest me wht I need to do