We have ways of downgrading your machine: better not try to use Outlook 2003 on a machine with more than 1 GB of RAM - MS can't count that high:
Still no luck there, though. I had to do a Google search to find the relevant page on MSN. There I find the "cause" of my tribulations (emphasis mine): If you are using Outlook 2003, and have more than 1GB of RAM available on your machine, you may encounter problems with Outlook. This is a known issue in Outlook, and a fix for this will be available shortly from the Outlook team. To avoid this problem, you can remove memory so that your computer has 1GB or less of RAM, or you can disable memory above 1GB.
Shades of "640k is enough for anyone" :)