Look behind the computer and locate the sound card. The sound card has a few 1/8-inch jacks in it, each a different color.
Plug your microphone into the microphone jack. The microphone jack should have a small engraving of a microphone next to it. Some microphone jacks are colored red.
Click on the "Start" menu on your computer, and select the "Program" tab on the menu that pops up.
Select the "Accessories" option on the menu that opens up.
Select the "Entertainment" option on the menu after the "Accessories" menu.
Choose the "Sound Recorder" program. This will open the recording program that came with your computer.
Press the red dot that is to the far left of the program's screen. This will begin recording.
Press the "Stop" button, or black square to stop recording.