1.) Windows Mail is intended to be replaced by Windows Live Mail, which also offers additional support. I suggest taking this opportunity to make the switch.
2.) When you attempt to send the email by manually syncing (press Ctrl + M), what error message is displayed?
I have 2 desktops and one laptop; one desktop with Win XP which is the one my modem and router are wired to, one desktop and laptop with Vista, connected wirelessly. My Vista desktop can receive email but not send, and my laptop does both. I checked the settings under tools and accounts, all are identical. Anybody have any suggestions? Thanks.