Peter,
No, I don't think any networking stuff is the cause, it's just that in an
office where you log in to a domain, the administrators can use policy
controls on the settings of the user's PC. For instance, if they didn't want
users installing software or if they wanted to place certain favorites in
everyone's Internet Explorer. One of the other settings they can control is
the IE homepage. I thought maybe you were in a office and the homepage was
getting reset everytime you logged in.
I did have a friend who used AT&T worldnet and it displayed this same
behavior as well. He would change the home page and as long as he was on
line it was fine; however, if he logged off and then back on, the worldnet
connection program would reset his homepage to AT&T.
There are some other places you can check in the registry, that will reset
the homepage, here is a link to an article about this problem:
http://support.microsoft.com/default.aspx?scid=kb;en-us;320159&Product=ie600
If you are not familar with editing the registry, you might not want to mess
with this. The article does suggest some other problems - viruses, spyware,
etc., but these seem unlikely, if the homepage is resetting to MSM, but
might be worth checking.
BTW, you said you tried to change the homepage to "Blank", does it do the
same thing when you set it to something else - cnn.com for example?
James