Hello fibola & Welcome to 7Forums!
What headphones to you have?
If it's Logitech etc. there might be some type of
driver or an utility. Look for their website, or either way, you might have a DVD with driver.
See if Windows have been putting up the right input for your microphone. Maybe the default input is broken, who knows!
Also make sure the software you're communicating with is functional.
Good luck
Best Regards,
FredeGail