Start - Accesories - Entertainment - Sound recorder. Also, when you open it, go:
File - Properties - Convert now - (under name select) CD quality. Ok it all.
Now, I see you have a creative card, so you probably have the little creative speaker logo (the white and blue one) in your system tray. Double click it. If its anything like my Audigy 2, you'll get a little mixer. You want to set the REC red fader up to "What u hear" input. Now find the mp3, hit play on it and press record on sound recorder when the bit you want starts. Stop when it finshes
I was assuming this was from an mp3 you can only open online (quicktime or something). If not, you could download Audacity (google it), open the mp3 file in it and cut the bit you want out (its pretty easy to use)