Headset not working as intended

I have steelseries diabol 3 headset, the audio is working perfectly fine. The only issue is that
my mic isn't capturing everything I'm saying. When I skype with others, Sometimes they hear what I'm saying, sometimes they can only hear part of what I'm saying and sometimes they don't hear anything. I have tested with another computer and it seems to be working perfectly if I switch to another computer. So I'm pretty sure there's something wrong with my original computer and not the headset itself. Thank you for your time.