Check the BIOS also, some allow disabling of the USB 3.0 controller altogether. In which case, you shouldn't have any problem as long as you're using the ports designated USB 2.0. Then after W7 is completely installed and have the chipset INF software installed, restart then enable the USB 3.0 controllers and install the drivers from Windows. Also be sure to use W7 install media patched to SP1.