Outlook Account Settings are getting changed randomly without my knowledge

Can Windows 7 critical updates mess up outlook email account settings?

Twice this week a few days apart I could not send email (I could receive though), becasue some of the settings in advanced had been changed. Also outgoing was changed from pop. to mail.

I assume when I write an email and hit send that it is sent. It becomes a big problem in my business dealings when i assume an email has been sent but it just stays in Outgoing Folder.

Is there any software that warns you that an email you sent has not been sent?

How do I avoid this problem in the future?

Is tghe problem caused by something other than Windows updates/. Maybe a virus or malware?