"Paul" none wrote
Unless I'm mistaken (in which case I would appreciate being
corrected!), Outlook Express 6 doesn't allow you to block either:
1 messages larger than a certain file size (as opposed to
number of lines); or 2 messages with attachments.
This is a pity.

You can get OE 6 to not allow the opening of attachments
that may contain a virus but it's either on or off and there's
no settings available. You can also use a message rule
that deletes all messages from the server that have
attachements.

And with message rules you can delete (or move) messages
that are greater than "x" bytes but I'm not sure if that works
with just the message or with attachments too.

Jordon