550 Outbound mail refused - no from/sender header [R0111001] I can't send email. Roadrunner says it is in outlook, I can send/receive OK using RR. I tried using "repair" from Control Panel Programs & Features, no luck How can I uninstall just Outlook from Office 2007?
Go to Tools -> Account Settings. Then select the default account and click on Change in the toolbar. Make sure there's an email address entered in there. If there isn't you'll need to enter one before you can send email (hence the "no from/sender header" message).
Hope that fixes it for you :)