I have the same N-series laptop (Asus N56VM), it has only usb 3.0 ports and it will crash with audio devices, not only the S2 /s4.
You can disable the USB 3.0 ports in windows 7 by installing 2.0 drivers, but I recommend windows 8 to get the most out of your computer. It fixes all hardware issues and gets your pc on par.
I tried disabling 3.0 it myself, but then I ran into various issues (like using outdated drivers) that I don’t want on a new laptop.
So I upgraded to windows 8 for a few bucks, now my laptop runs very stable and lightning fast. I use it as a music workstation only and for that task Win8 is very suitable.
Now I don’t say Windows8 is a great OS (it’s not) but it runs very smooth with low resources and most drivers for the N56 are updated for windows 8.
So for real performance on a neat machine like the N56 I would say that’s the way to go.
Really, Traktor+S4 runs great on the n56v after the windows 8 upgrade.
Only thing this OS needs to tweak is disabling live tile animations and schedule the maintenance settings,
less then 1-minute work to get most out of this powerful machine.