Mic Help Please

Hello, I Got A Koss SB/45 Headset The Mic Is working and its completly new
I had an other headset before but it broke but the mic still worked but Something is wrong with my computer I cant Talk with them I dont got them on mute or anything They work in ventrilo And teamspeak but i would like to use them for other things like steam gaming, gaming and tutorials. Please Help Im Desperate (actually not but...)