Service Pack 4 install advice

I was listening to a Microsoft technet seminar yesterday and they had some good advice on installing ServicePack4. They said to copy across msconfig.exe from a WindowsXP machine, Boot the w2k machine and run msconfig.exe. Select the services tab and then select Hide Microsoft Services. You are then left with all Non-MS software. Select disable all. Select the startup tab and disable all of these ones too. When you next reboot you will be left with a "clean" install of Windows. You should then be able to install ServicePack 4 (or whatever) without anti-virus or other software clashing or interfering with the install. Hopefully this will help out Barbier who posted a question on my previous post about Service Pack 4 installs.