I know you say it is a fresh install. It is amazing how quickly users can download and install things that mess things up. I would take a tour through her add/remove programs. Look for installed tool bars like Smiley Central etc. Look for adware. Open her outlook and look and see if there are any additional toolbars installed at the top. Outlook 2000 was easily frozen by these things. If you find any uninstall them and restart Outlook. Is this an exchange account or a POP3 account? Another thing to look at is their stationery if they are using one. Users will download stationery they like and Outlook 2000 may not like it much. The freezing on sending or forwarding makes this a possibility.
Make sure her version of Office is patched with the latest service pack.