Which is the best thing..

[UID=0]

If you dual-boot, with 2 instances, of the same version of Windows,
then it may be possible to run a different AV application on each OS.

It may be dependant, on whether the alternative OS, is installed onto another partiton, but it may also work,
even if the 2 instances of Windows, were running side by side, on the same partiton, in folders called Windows and Windows1 respectively.

In fact, I did this fairly recently, some months ago, when I tried out AVG, Avast and Avira, in a relatively short period of time, but I can't
exactly remember now, whether they were on seperate partitons in all cases, but I know that they were in some cases.

It would probably be better though, to install the alternative OS, onto a different partition,
which after all, is the recommended method of dual-booting.

This may be advantageous, as it may allow you to test out several, AV applications, on one OS,
in a relatively short period of time, while keeping your favorite AV application, on the other OS.

Having said that though, running multiple versions of Windows on the same partiton, has always been problem free for me,
as my current OS, runs from a folder called Windows2, but there are also folders called Windows and Windows1 as well on the same partiton.

I can just delete the older Windows folders, whenever I want.

I am not sure if this would work for firewalls though