Mic Won't Pick Up Voice?

i have windows 7 64-bit with realtek on board sound and i can't get my mic to work and as i and my friend try to fix it we realize that that mic won't pick up my voice but my friends hear what i hear on the pc for example if i put a music on the pc from Internet my friend will hear the music but not my voice, i have a razer carcharias headset and yes i plugged it right and i even tried on my dad's laptop he has vista and it worked fine. and fyi my mic worked perfectly before but all the sudden it stop working, one dad my pc crashed because the graphics card got loose and i turned it back on and i realize my mic is not working anymore. i pretty much did almost all the procedures, will buying a sound resolve this problem, by sound card i mean a actually sound card or a external usb 1, it depends on which i can afford.