New PC build audio not working through jacks (not plugged in)

My newly built PC does not output audio from any of the tower jacks. I have to plug speakers into my monitor which are connected by HDMI in order to get any playback devices recognised. This is an issue as i cannot use headsets including using a mic. I have tried nearly everything such as showing disconnected and disabled devices, and also installed all sound drivers such as realtek and also NVIDIA high definition audio for my graphics card. I have also opened up my case to see that the cables for audio are plugged into the motherboard correctly.

My playback devices menu shows my monitor as the only source of audio. while any other speakers or headsets i try to plug in are not recognised. Has anyone had an issue this unsolvable before? Should I just take it into a computer store and pay to get this fixed, as i'm starting to doubt that it is a simple fix.

Assuming the mother board in your system specs, having Googled the manual, look at the bios, South Bridge Configuration, HD Audio and Front Panel both have enable / disable options.

You have on-board audio (Realtek on the motherboard). First thing, check the BIOS as suggested to make sure the on-board audio is enabled. It could very well be the BIOS, as Windows is not detecting the on-board audio (Realtek). If the sound is enabled in the BIOS, reset the BIOS.
Then reboot and after Windows has initialized check to see if the sound is detected and installed. With Realtek, Windows normally installs the correct Realtek sound driver.