Onboard sound is hissing and makes static noises

[p.m.mail87]

Hello guys,

First of all please excuse any bad english

My current problem:
My front audio output gives out no sound and my output on the back only makes hissing and static sounds.

I checked all my drivers and the noises are still there wether or not I disable or enable my sound devices. This problem occured after I put my graphicscard back in, because I took it out to dust it off. I was very carefull in the process. Also I checked every wireconnection, in case something is not but in place correctly.
No problems occured in the latency test I did (this was suggested by some other threads I sifted through). So after 4 hours of google search and no results I ended up here

My Mainboard is the ASRock Pro3 R2.0

Thanks in advance for anyone who tries to help.

Edit: Tried resetting the BIOS but no changes. When I shut down my pc it starts peeping through my headphones. Another thing I noticed, strangely the hissing intensifies when I change from power saver mode to high performance.

Edit: When I put on a track and blast it on max. volume I still can hear the bassline and the voices very very quiet.

 

[RARRAF]

not to sure but just an idea check all the grounding screws are tight holding motherboard to case with a screwdriver.

 

[drea.drechsler]

Does disconnecting the front panel audio connections from the motherboard header pins improve the sound at the rear jacks?

I'd also suggest making sure all the mounting screws are in place and tight, with standoffs underneath also tight to the motherboard tray.

Lastly: make sure your default audio device is the same as where your speakers/headphones are jacked in at.

 

[p.m.mail87]

not to sure but just an idea check all the grounding screws are tight holding motherboard to case with a screwdriver.

Does disconnecting the front panel audio connections from the motherboard header pins improve the sound at the rear jacks?

I'd also suggest making sure all the mounting screws are in place and tight, with standoffs underneath also tight to the motherboard tray.

Lastly: make sure your default audio device is the same as where your speakers/headphones are jacked in at.

Thanks for the suggestions.
All motherboard screws and standoffs are tightly in place, but no changes.
Disconnecting the front panel audio sadly makes no difference eather.

Hers´s the thing I discovered today:
When I disable all my audio devices in the device manager and restart my pc the noises stopped. So I first enable all the Nvidia audio device and everything was still quiet, which didn´t suprise me because they give out the audio only via the display connections. But when I enable the Realtek driver the noises start again. So I deinstalled all Realtek drivers and restarted my pc so the Windows default drivers would install themselfs. As soon as I started my pc the hissing noises start again. So I disabled the Windows default driver and restarted my pc and the noises stopped again but again when I enable them the noises come back.

That leaves me with the conclusion that it is a hardware problem? But I am really no expert so I wanted to hear your opinions on that.