If you have virus problems that get past Microsoft Security Essentials, nothing like using Combofix. I've been using it for years and I am really happy with it, it has saved my computer once from reinstall because it could clean it effectively. It's a one time run, free anti-virus, so no major concerns really. Has anyone tried it?
I've never heard of it to be honest, I've never had much trouble with just using Security Essentials and that's all I've used for a couple of years now. But do you install Combofix in parallel to MSU or does one replace the other?
No, Combofix is one time run anti-virus, you don't need to install it, you just download the file and run it. Basically Combofix will detect and remove all the virus on the computer, it's like a bomb that kills everything, so just beware if the operating system is too compromised, parts of it will be removed because they have the virus, but this is an extreme and uncommon case.