This song was the "B-side" song from the Yuzurenai Negai minidisc.
I had been looking for this song for yeeeeears until now. I had to upload it right away. It is sung by Naomi Tamura

Ano Hi No Futari Wa Mou Inai (The couple from that day are no longer here)

If anyone wants me to email them any of the songs I have uploaded, feel free to send me a message or download the program Video2MP3. Your can search for it on Google. It is a program that lets you download the audio from any Youtube video. Very very useful!