I've uninstalled Norton and done everything you all said (problems mac
suggested were already done and checked, so wasn't that causing problem). But
original problem is still there. I've discovered that send & receive only
doesn't work when there is mail in the outbox. If no mail in outbox, send &
receive works :/

Yet when I reboot Windows Mail, it sends any emails in outbox.

And when I deleted an email in outbox, it still showed a (1) next to outbox
indicating there was an email in there when there wasn't.