I am having problems getting emails out of my PC.

To make things easier I shall briefly state that...

1. This is NOT an ISP issue.
2. This is NOT a web host email server issue.
3. NOTHING is blocking ANY ports or traffic.
4. The smtp & pop URL are the "SAME" url, eg. mail.mydomain.com
5. Ubuntu moans about my desktop name being an "Unqualified Domain Name"
6. I installed Sendmail and MTA as indicated in the Ubuntu FAQ / Trouble shooting guide
7.I have repeatedly asked over the last 3 months for help on this but get lame assed replies that do not help.

I will admit that I am very new to Ubuntu, so anything tech will "A380 Airbus" on me and my eyes will glaze over and my head will possibly pop under the strain...

The question is this, how do I get my emails going out when I have no issues collecting them? Remember that the URL is the same for incoming mail as it is for out going.

I have used Opera and Evolution clients and both have same issue, under WindowsXP Opera has no issue collecting and sending emails. As I do not want to keep firing up my laptop every time I need to send an email and for practical purposes... I would like to solve this issue and would like to resolve this seeing as the Ubuntu community are sitting on their hands with this issue.