A few more things to try. First would be a hard restart. Power off the laptop, unplug the battery and charger, and hold down the power button for 30-40 seconds. Then boot it and try the mic again.
If that doesn't work by itself, try going into the realtek audio manager (or whatever audio manager you might have) and seeing if any other mics are set to active. I usually have to change mine there even if the correct one is set to default in windows. If you have one, they usually pop up if you unplug and plug back in the headset.
Finally, i know you said that your drivers are updated, but I would do a clean install to make sure nothing is corrupted. Go back into the device manager, click the "audio inputs and outputs" dropdown, right click on your mic and click "properties," and uninstall the device. Power off the computer, and then boot it back up. It should scan and automatically download the newest drivers.
To be honest, if those don't work I would begin to wonder if the jack or the headset had gone bad. Can you get your hands on another headset to test?