Is this headset plugged into the back panel of the board (i.e. the same green connector that your speakers were plugged into)? If it was plugged into a front panel connector on the PC, try plugging it into the back panel of the board and see if there is a difference. If there is no difference, the problem is in the headset.
If you are plugging the headset into a connector on the front of the PC, unplug it now. What happens? You should see a pop-up message, when you do plug it in, do you see an "Information" notification box saying the headset was unplugged? If you plug it back in, you should see another "Information" notification box saying you plugged something in. You should also see two Realtek HD Audio Manager windows, the first asking you first what you plugged in and the second offering you with some configuration options. Are all these things appearing?
Let us know answers to questions and what happens as you follow these instructions...
You never said; when you plug in the headset, do you see the Realtek dialogs?
When you say speaker volume is ok, do these speakers have a built-in amplifier? Why do I ask this? It is possible that the amplifier on your motherboard has given up the ghost and your speakers are only working well because of their built-in amplifier.
If you want to keep this system alive much as it is, you have a couple of alternatives,
- Purchase a PCI or PCIe audio card. There are many available for less than US$10 (PCI example: https://www.amazon.com/Channel-Surround-Audio-Desktop-Computer/dp/B01BUTKEEQ Amazon.com: Gotd 4 Channel 5.1 Surround 3D PCI Audio Card. PCIe example: https://www.amazon.com/Express-PCI-E-6channels-CMI8738-windows7/dp/B01COIAPUA Amazon.com: PCIe 5.1ch 6channels CMI8738 3D Audio Sound Card) though I would go for a slightly better quality solution myself. If you go with this type of solution, remember to disable the motherboard's audio subsystem in BIOS Setup.
- Purchase a USB-based headset. There are some good ones for less than US$30. For example: https://www.amazon.com/Logitech-ClearChat-Comfort-Headset-Black/dp/B000UXZQ42 Amazon.com: Logitech ClearChat Comfort/USB Headset H390.
- Convert your existing headset into a USB headset. There are solutions for doing this for less than US$10. For example: https://www.amazon.com/external-Adapter-Windows-Microphone-SD-CM-UAUD/dp/B001MSS6CS Amazon.com: SYBA external USB Stereo Sound Adapter. I have a couple of these and I use them all the time with speakers and headsets; they work great and need no drivers or external power. Considering that your current speaker solution is still working, I believe that this is your best choice...
Hope this helps,
This motherboard model was released on 2009; however, Intel provides with 3 years of warranty since the date of purchase. If you have the proof of purchase of the board; I suggest you to contact our support center and request a replacement.