I've tried everything but still can't send plain text. The chances are that your organization is using Microsoft Exchange Server and has disabled the selection of message format by individual users. Under Exchange Server 2000 it is the same setting, but its location is different. Messages don't look the same when posted as they did when I sent them. Several issues conspire to spoil the layout of plain text messages.
Most email clients display plain text messages with a similar font.
These may be translated differently by email clients. Avoid using the tab key. Tabs can be interpretated differently by email clients. Our list of members is protected. Plain text is the only format accepted by all email clients.