Your case with have an audio cable that runs from those ports, through the case.
It's intended to plug into an audio jack in your motherboard.
In your user manual for the motherboard, look at page 1-3. Item 14 is for the front panel audio connector. Here's a link to the manual if you don't have it handy.
http://dlcdnet.asus.com/pub/ASUS/mb/LGA1150/B85-PLUS/E8452_B85_Series.pdf
If you know you had that right from the beginning, it may be a driver issue.
Your motherboard came with a disc. If when you insert the disc, it doesn't autostart, search the disc for a program called something like "setup". Run that. From there, you'll get a small program where one of the tabs across the top should say "drivers". Click on that tab.
From there, click on any or all the drivers. If you don't want it all, make sure you install anything along the lines of anything audio.
If you don't have the disc, check out the link below. Make sure you pick the right version of whatever operating system you're using then click the text that says "AUDIO". Download the file it shows, unzip it, and run the program found inside.
https://www.asus.com/Motherboards/B85PRO/HelpDesk_Download/
If those solutions don't work, report back and we'll try to figure something else out.