You should create a new Unicode PST (File>New>Outlook Data File), make it
your delivery location (Tools>Account Settings, Data Files tab, select the
new PST, click Set As Default), then stop and restart Outlook.  You will
have a new set of (empty) default folders and another folder set that is
your old folders.

Open each old folder and select all the entries in it by pressing CTRL-A.
For the Calendar folder, you'll have to choose a table view first, though,
like By Category, before CTRL-A will work.  Then click Edit>Copy to Folder
and specify the corresponding (i.e., same name) new default folder as the
destination.  If you have any folders you created yourself, you can copy the
entire folder.  WHen all the copying is done, close the old folder set by
right-clicking its root and choosing Close.