From then on it takes about 2+ minutes till the red cirle is gone and Avast is operational, which usually happened within seconds.
On Windows Events (Control Panel > Administrative Tools), is there any service error logged there?
Try
Startup Delayer to control the Windows startup (Windows 98\Me\2k\XP) that does not follow a strict order.
They will manage the execution of programs that are automatically started by the operating system at logon time. Instead of executing many programs at once (causing your OS to spit and sputter and attack your hard drive), StartRight will give the OS time to execute the program before running the next program. The OS should become much more responsive almost imediately after logon.
Since avast! version 4.7.807 the Standard Shield has a feature called
do not scan system libraries (by default on) that dramatically decrease the number of files scanned during computer boot.
Curiously enough only after that my Kerio personal firewall service shows up with it splash screen, usually it's on of the first things I see right when the desktop comes up. Somehow Avast seems to wait for something not allowing any of the regular services in the background to work, I even cannot connect to another PC in my LAN, since the network is not available yet. How come?
You need to go to 'Logs & Alerts' page of settings of Kerio and disable the option to 'resolve address'. Sorry, I've used Kerio in the past, I can't post a screenshot anymore.