Outlook Express isn't a calendar program. It's a mail and newsgroup program only. So I doubt if the Ipaq says such. Maybe it says MS Outlook? I'm sure you can buy that for Windows 7 64 bit.
Moreover, Outlook Express isn't supported for anything higher than Windows XP. Microsofts current mail program that replaced it is Windows Live Mail.
I am running Windows 7 64bit and when I try and sync my Ipaq RX 1950 through WMDC, it says that in order to sync the dates etc - I need a program such as Outlook Express.
I have two questions about this:
1. Can I use a calendar program other than Outlook Express?
2. When I try to find and download a opy of Outlook Express it mentions something to the effect that it won't work on a 64bit OS.