Sometimes an OST file becomes corrupted beyond repair or repair is not desirable. In this case, it can be deleted. After it had been deleted, you may need to recreate it as a new file as described above before Outlook will work properly.
• Quit Outlook if it is running.
• From the Start menu, go to Run.
• In the Run window, enter this command in the “Open:” field and click OK:
o “%USERPROFILE%\Local Settings\Application Data\Microsoft\Outlook\”
To find the exact path, please follow the steps 1-4 for Outlook 2002/2003/2007 or steps 1-3 for Outlook 2000 outlined above to get to Offline Folder File Settings. You can find the .ost file location in the File box. You may want to cut-and-paste that information for accuracy and ease.
• In the Explorer window, locate the OST file to deleted. Select it and press delete on your keyboard or use the Delete icon on the toolbar

Set the default startup directory

Click Start, Run and type Regedit.exe
Navigate to the following branch:

HKEY_CURRENT_USER \ Software \ Microsoft \ Command Processor

In the right-pane, double-click Autorun and set the startup folder path as its data, preceded by “CD /d “. If Autorun value is missing, you need to create one, of type REG_EXPAND_SZ or REG_SZ in the above location.

Example: To set the startup directory to D:\learning\perl, set the Autorun value data to CD /d D:\learning\perl

You may also use a batch file so that it executes the contents automatically upon launching the Command Prompt. To view the entire list of arguments supported by CMD.EXE and their description, type CMD /? at the Command Prompt.