off the bad this sounds like a faulty unit but before we say that we should run further tests.
Can you connect the SB2's to another pc, I have had issues with SB2's not working via hubs, sometimes some pc's come with hubs onboard and it wont work via that (it seems it needs some comms with host before this works)
if it works via another pc then we can assume its the PC/HUB/OS thats causing a fault.
remove the downloaded driver and reconnect the device, the system should see the unit as a HID sound card, i've confirmed this on windows xp/7 as my old DJ laptop was dualboot XP/7 and it worked fine without any drivers, i only install the drivers to access AISO modes which work better in Win 7/8/10 than standard Sound IO.
try another sound APP, media player or similar that does audio.
final test/solution is download a copy of ubuntu for USB flash drives and boot ubuntu, if it works under ubuntu then 100% it's your OS, this requires a reinstall of the Windows OS if you want stability. there is a app under ubuntu called MIXX which works with the SB2's and you can test it even with USB ubuntu by installing the app via the software center.