There are a lot of different kinds of microphones out there and most don't work plugged directly into a computer. You need an amplifier between the mike and the computer that will match the impedance of the mike and provide a "Line level" output to be fed to the computer. If you have the amplifier that came with the Karoke mic, look at the back to see if there is an output labeled aux output or line out. If there is, feed that into the computer. If there isn't, electronic supply stores sell inexpensive mixers that will input the mic and provide a line level output.
