How to control "My SharePoint-Websites" in Office 2007

This is an annoying problem that's haunting me for month:

In any Office 2007 Open & "Save as" dialog box there's a location selector

for "My SharePoint-Websites". In this location there are a number of

SharePoint sites that have accidentaly been memorized here. As the owner of

some of these sites has not given permission to me to access these sites,

trying to access one of those will pop up a login box and that's exactly what

happens in any Office application (Outlook, Word, Excel, Powerpoint, etc.) at

random times. I'm not aware of any special user action that triggers the

connect, so you couldn't even avoid it by not opening and saving any files.

You can find out the Office application causing the connect by the

application tab that's assigned to the "Connect to " login box. As

the box always comes up again when you click Abort, the only chance to ger

rid of it is to shutdown the responsible application thereby closing all

normal windows you have in this application. But of cause this is only a

short term solution as some times later the next Office application starts

the connect problem again. I tried to empty the directory that represents

this locations that can be found under \local settings\application

data\Microsoft\Office\My SharePoint-Websites, but the entries are

automatically recreated, so this didn't work.

(BTW: I translated directory names from what they read in German, so they

might not be literally correct for the English Office.

Does anyone know where these locations are memorized in Office and how to

control what's stored there? I'm not aware that I got any SharePoint list or

calender on one of those sites connected to Office, e.g. none of them is

listed in the SharePoint-Lists Tab of my Account Settings in Outlook, so I

just don't know where to start besides going deep into those thousands of

registry keys that might contain those cumbersome references.

Help!