Asus Xonar ST won't work with digital out put. Please help!

I have very strange issue with my Xonar ST

My story begins about a half year ago.
Back then, I was using HT omega Claro sound card. I loved it and had great sound.
However, After I updated Logitech web camera/mic driver. My sound card stopped working. But only digital out put stopped working. Analog was fine.
I contacted customer support. They gave me new driver for my Claro. The sound card started working again.
About month later, I installed Bluetooth USB receiver and then, same problem happened. Digital out put stopped working.
I contacted customer support again and I got another patched driver from them. The problem was solved again.
After about month later, suddenly with out no reasons, the sound card stopped working again. This time no mutter what I did, digital signal didn't came back. I was using the card with analog out for a few monthes... but I gave up the card. I thought the card's driver have bug or something.

I purchased Asus Xonar ST few days ago instead.

I installed the card and tried to use the card but same problem happened. The digital out put won't work!!!
I tried everything. Uninstall & reinstall driver, disable on board audio from BIOS, I even tried to reinstall my Windows7. I was straggling few days and I don't remember what I did exactly but the Sound card stared working!
It was working Sunday whole day. I thought I solved the problem but next morning, same problem. Digital out put is not working.
I straggled hours to solve the issue and goolged hours but The digital out put doesn't work.
One thing I just found is actually HT omega Claro and Ausu Xonar ST has same Chipset: C-Media(?). That's why symptom are same(?)

Also while I was straggling to solve this issue, I realized the problem which happened earlier, I thought caused by a web camera or a Bluetooth might have not been related to this sound issue.

Right now, after researching days, I feel like this problem is caused by my gaming graphic card Ausu EAH6950 DCII/2DI4S/2GD5
This card has audio maybe related...Of course I'm certain.

Today I called Anus tech support but they have no idea.....They are just saying my computer has too many sound and have to disable other. Which I did!

Funny thing is that if I go to Xonar Audio Center and try to click speaker to test sound, about 1/5 work.
I mean, if I keep clicking test speaker, one in awhile the sound work. Very strange.
Also Analog out put has no issue at all.

My computer spec is like this.

OS: Windows 7 Ultimate 64bit
CPU:AMD Phenom II X4 695 3.40 Ghz
Motherboard: Asus M4A89GTD PRO/USB3
Graphic Card: Asus EAH6950 DCII/2DI4S/2GD5
Sound Card: Asus Xonar ST
Web Cam: Logitech c910 pro

Please Please someone help me!!!

Odd to say the least. Could be power related prehaps?

Does the card work right when all the blutooth devices are removed?