Sorry, I was in a hurry.
I hope you run Windows 95/98/ME
First: Run "Sndvol32.exe". That will open a mixer.
Choose "Options\Properties..."
Select "Recording "
Make sure that "Wave Output" or "Mixed Output" is marked in the list in the bottom of the screen.
Click "OK"
Now mark Choose under Mixed Output or Wave Output (depends of Version (You shall only have one of them))
(You may have to adjust the level of that volume too. It might require some tries to get the right volume)
Now your computer is set to record what is played in the speakers.
Run "Sndrec32.exe". That will open The Sound Recorder.
Press the Button with a red filled circle on it (Yes, I mean the Rec button).
Now, soundrec will record all sound that is played by the computer for the next 60 seconds. Yes it is a short record, but I think it will be enough for you to play that animation in the sequence where you want the sound. If not You will have to record nothing for the time you need (by starting the recorder again after 60 seconds) or you have to download another recorder.
After you have recorded the desired sequence you will have to trim the sound to just contain that. Play the sound until the sequence begins, stop it and select remove everything before current position from the edit menu. Find the end of the sequence and remove everything after.
You may want to save the uptake before editing.
You may also have to turn off all Windows sounds while recording.
I have translated all menu options from Swedish, so they may be in other names, with almost the same meaning.
I hope this clears things up.