[EthanHarte]

I recently built a new computer and decided to put an Asus Xonar Essense STX sound card in it. Yesterday I was playing some music pretty loud (I went downstairs and wanted to still hear my music) and when i was downstairs, the music stopped playing for a second and then continued. I went upstairs to see what happened and only my front right speaker was working. So i tried other sources like an iPod and a laptop and those worked fine. It was only when i was using my computer so i think it is the sound card. I took out the card to check for blown capacitors and i dusted it off. It looked fine so i put it back in and i was still only hearing sound out of the right front speaker. 
 
I checked if it was software by reinstalling the drivers and something weird happened. After the reboot of the computer, I was able to hear sound out of every speaker. BUT, when i turn down the volume on my computer, the volume of my speakers become out of sync (the right is louder than the left). When i have the volume all the way up on my computer, the volume of my speakers becomes synced and sounds how it should. Because of this I have made a temporary fix. If i turn the volume all the way up on my computer (syncing the volume of the speakers) and I use the receiver volume as my main volume control, it will act like it should. The receiver does not make the volume of the speakers go out of sync.
 
I am really confused because i have read about people having a high pitched noise from the right speaker or a hiss from the right speaker. My issue is similar to theirs but slightly different. Is it software or hardware?
 
Set Up:
 
-My computer
   -8GB RAM
   -64 bit Windows 7 Home Premium
   -Asus Xonar Essense STX sound card
   -MSI R7770 Graphics Card
   -BioStar TA75 MH2 Motherboard
   -AMD A series A8 Processor
 
-My System
   -Pioneer Elite vsx-40 Receiver (connected to the sound card via digital optical)
   -Front Right, Front Left, are Klipcsh RB-61
   -Center Channel is RC-52 II
   -the surrounds are an old pair of JBL
   -the subwoofer is an old pioneer
 
-My Software
   -Audio format is 24 bit flac
   -Music program is Foobar
   -I am on the newest version of the xonar driver and software
         -48KHz
         -2 Channels
         -2 speakers
         -PCM is checked
 
I am only 17 and dont know much about speaker software or equipment so if i am doing something wrong with the settings or some simple mistake be sure to let me know.
Any ideas or help would be greatly appreciated!
Thanks!
-Ethan Harte