Outlook 2010 acting very strange

[Exfso]

I regularly send myself an email if I find something useful and save it in a folder under the inbox. Up until a week ago this was working fine, now any email self addressed disappears for almost exactly 2 hrs. If I use windows live mail or Thunderbird this is not a problem, the email virtually comes straight back to me.


I have uninstalled Office 2010 and re-installed, problem still the same, and this is prior to all the updates that come in as the result of a re-install. Ok so updates are ruled out.
I have checked with my ISP and they had a remote link up with me and gave up in disgust after 90mins. I notice they use an anti-spam called IronPort. In case this was the problem I disabled it in my preferences on the site.
I originally thought it was the bunch of office updates that came in during the week, but as I said the issue happens with or without them installed.
I have a laptop similarly set up and it is doing exactly the same.
In addition I have a couple of email addresses with my ISP and this is happening on both of them.
All other emails from outside are not effected.
When I address a message to myself and send, it goes straight into the outbox and almost immediately is sent. This is confirmed by checking the sent box from within Outlook.
I fail to see how it can be my ISP as surely the problem would happen using other email clients. Incidentally, sending email/receiving email from my IPhone is normal as well.
A couple of people from various Office/windows 7 forums say it is definitely an ISP issue, they are saying it is an Outlook problem. I have been using Outlook for years and this is the first time this type of issue has come up.

Just as an update, these self addressed emails are now disappearing totally, no sign of them at all, it is as though they are gone into the mist never to be seen again.

I have a friend who lives around the corner from me, with the same ISP and his Outlook is behaving normally.

Any help on this one very much appreciated.