Sporadic system freezing at startup.

In six months of Avast!Home Edition use, I have had the (little, because very sporadic) following problem that I would like to signal: for 3 or 4 times (in six months; I use my pc every day), at Windows statup, in the moment which the taskbar icon of Avast appeared (this had the little red circle) the system immediately freezed. It was not possible to launch any application, to move the mouse, open task manager or exit from the system: the only way to decontrol has been to force the turning off with the button on the machine. At the following reboot everything has returned normal, without any problem, and in Event log was nothing about.

Before the installation of Avast, this had never happened; I had Norton AV 2005 that I have full uninstalled also using the tool SymNRT.
I have also checked the ram, with an appropriate tool, but all appear right.

Often, instead, the taskbar icon of avast appears, at startup, with the small red circle for few second, then everything regularly goes (this don’t appear as a problem).

The resident shield configuration of Avast is positioned on Hight, for control all the files.
I access to the system using the logon screen (this should help the automatic start of all the processes before the logon).

My PC is a laptop Acer, Pentium 4 2,6 Ghz, 512 MB ram, Win XP sp2 (fully updated) and I use Windows Defender as antispyware, and the standard Windows Firewall.

The issue is sort of conflict, perhaps, with Windows Defender?
Any suggestion?

If it is only for a few seconds it shouldn’t be an issue provided it does clear and the avast processes are running in Task Manager, ashServ.exe, ashDisp.exe, ashMaiSv.exe, ashWebSv.exe and aswUpdSv.exe.

There have been some theories that it is to do with the slow loading of a service that is required by avast that causes this and once loaded avast is OK. However, no one has pinned this down exactly which one or what might be slowing it.

Not everyone experiencing this has had windows defender

This theories include Microsoft Updates (today we have some ones), Windows Defender updates, etc.
Other theories say that windows startup which, for sure, does not follow a strict order, need to be tweaked in some way and use Startup Delayer. This tool 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.
Remember that 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.

I hope that the developers investigate and that in future versions of Avast this problem is definitely solved, so that this very good program some more good becomes!