headset not working with dell xps m1730 laptop?

[Ryan]

handed down by a family member i figured this was gonna be great but turned out with only big flaw for me..i cant speak?i mostly use skype and i can hear the other on the call fine and anything else is fine but no matter what i do i cant talk.if it helps i am using a piranha razer headset.im sure this is a harder question than most but it is very important. thank you