It would be useful to give us some hints on how to simulate the problem. AFAIK this is no repro in our test lab...
WinXp/SP2 + latest fixes from MS.
IE6 + latest SP and fixes from MS.
Avast 4.7 HE, auto updated as needed.
Comodo Personal Firewall, latest version (I believe, not at home right now).
Windows Live messenger (does it matter?)
Homepage set to google.ca
Avast has WebShield turned on (turning it off fixes the problem)
CPF has Application Behavior Analysis turned on (turning it off fixes the problem)
1) Reboot.
2) Start IE6.
Instead of going to the homepage, IE displays a popup as below:
... When I try to open Google's main page with Web Shield enabled, the page does not load. Instead, I get a popup stating that I'm about to download an application/octet-stream and it asks if I want to save it or open it with another application. This happens only when both Web Shield and Comodo Personal Firewall are enabled. It does not happen if either is disabled.
More details can be found here:
http://forums.comodo.com/index.php/topic,3113Currently, I have disabled WebShield.
An interesting side effect: web browsing feels noticeably quicker!
What other information would you like me to supply?
Since I have exactly the same symptoms as neiby, perhaps it is possible to cross-reference?