To change date formats goto "control panel" then "regional and language settings" click on customise.
Then in Outlook's office assistant type "date format" - you will be given several options (also see "more options") There is a multitude of format settings to look through.
If all of the above doesn't work and you are sure its because you didn't install the complete package then uninstall the lot and reinstall - your data files should be left - but just in case do a restore as well as back up your data files.
I reformatted my system amd reinstalled Win XP Home. When I reloaded my Win Office Small Business apps, I used the express install. Unfortunately this less than full features version of Outlook does not include the 'day of the week' designation. In the home page it now only shows the current date. I tried to selectively install the full version of Outlook from the CD but there is no provision to do this. Version is dated 2002. Any ideas how to do this? I have lots of unused memory!