Please Help Me Identify This Piece

This is tricky, partly because I don't know where it's from and partly because I've only got one snippet of it in my head at the moment.

Happily, I managed to get the tune down (albeit on Mario Paint) and I uploaded it to Youtube, via this link.

The instruments in the audio clip are not original (obviously). The repeating bass notes represent the chord it's played over.

I think it's an instrumental piece, either solo piano or orchestral. I don't think it's a song (doesn't have a vocal part). It might be on a film somewhere, but again, I'm not sure.

Wow, that's really not much to go on, sorry! It's been in my head for the past week now and I'm taking desperate measures.

Thanks for your help :D