Greetings, roleo,
My experience was almost exactly the same. Mine loaded with all four modules working, but after I removed all but Outlook/Exchange and adjusted the groups value for testing purposes, I was unable to reinstall the other services using Add/Remove. My system locked up at the end of the add/remove process, and a hard reboot was the only way out. When I got back into Windows, I did a complete uninstall of avast!, rebooted, then reinstalled avast!. This worked fine, and after removing the groups value from the registry again, the boot process was back to normal.
(I didn't mention this in my earlier posts because I didn't want to introduce a new twist to the issue of tracking down the boot delay.)
I am currently running the four providers (standard, network, web, and internet mail), WITHOUT the "groups" registry entry, and everything is perfect. The system boots well, and programs run very crisply.
Best regards,
Crashman