So, are you saying you hear white noise along with the windows sounds and game sounds? Or you just hear white noise regardless of what is going on with the PC?
First thing to try, is going into the Device Manager and remove the sound card, and rebooting. Let the sound card reinstall, and reboot again. Device manager: right click on My Computer and Select Manage. Then, select Device Manager on the left from the Window that opens. Under Multimedia Controllers, find your sound card. Should say something similar to what you posted for specs. Right click, and remove/delete. Let it work, and close all your windows. Might prompt for a reboot, might not. Reboot anyway. Let it come back up, wait a few minutes and reboot again. Go back into the device manager and make sure the sound card is back. Check your sound.
Another thing to do is check online for updated drivers. The drivers will come from the motherboard manufacturer's site. So, that would be asus.com. Just go to support, find your motherboard under I think socket AM2, and look for audio drivers. Download and install then reboot. Probably try this before removing and reinstall via device manager.
Also, check your speakers/headset to make sure they are not the issue.
-Doc
"Can you put that in a memo, and label it, 'Shit I already know'?" - Sarge, Red vs. Blue