You often find this can be traced to extra mounting posts under the motherboard. We have to do this work again to really know.
http://download.gigabyte.us/FileList/Manual/mb_manual_ga-z97(h97)-hd3_e.pdf tells me only a specific jack will work for headphones. You tell me which jack you used.
As to the front audio, DO NOT PLUG IN ANYTHING to the F_AUDIO connections.
Failing you finding what's wrong the usual is this under 8 dollar fix: https://www.amazon.com/gp/bestsellers/electronics/3015427011/ref=pd_zg_hrsr_electronics_1_4_last
As to drivers, that's easy. Install the drivers you had working.
I recently had to take out my motherboard a couple times while dealing with a new heatsink and in the process my sound seemingly no longer works.
-I'm using the rear audio output jack as my front jack is broken
-I fiddled with the device manager but no available playback devices produce any sound when tested
-Messing with the Realtek HD audio manager also didnt produce any results
-When I updated it's drivers it now no longer launches at all
-Before I lost it Realtek would tell me it didnt support my device when I classified it as headphones
-The problem happens with several types of headphones so it isnt the headphone in question
-I suspected at first that maybe it was a misplugged wire but that doesnt make sense to me considering the rear audio output is connected directly to the motherboard
-The volume mixer shows audio activity when I play something on my pc
OS = Windows 7 Ultimate 64-bit (6.1, Build 7601)
System = Gigabyte Z97-HD3
Processor = Intel(R) Core (TM) i5-4690K CPU @ 3.50GHz (4 CPUs), ~3.5GHz
Memory = 16384MB RAM
DirectX = 11
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