.dbx files are data files of the outlook express mail client. this files will be created as per the folders we used in the outlook express. for ex. if you create a new folder name "myofficedata" then you will find a new file myofficedata.dbx in the data file folders. you can change the path by the following steps,
1. open outlook express -> click tools -. click option-> click maintenance tab -> click store folder and change it..
please make a backup before you format your system..
