I love moonlight sonata, also the forbidden act in vampire knight. Can anyone suggest more:

Criteria: classical or instrumental songs. Melancholic. It has to be the piano, violin, or both.
To Duchess Rodmilla de Marré, I do not know if you comment and question mean to be rude, but if my question was not important to me, than why would I ask it. Your question / comment is completely illogical. There are no premises for it. I can assure you that I have a passion for music, and because I have a passion for it, I want to listened to more of it.

Orion, by Metallica. I don't think it has any pianos or violins, but you'll probably like it anyway.

Waltz in C-sharp minor (Chopin)
Waltz in B minor (Chopin)
Waltz in E minor (Chopin)
Fantasie Impromptu (Chopin)
Funeral March (Chopin)
Prelude in C minor (Chopin)
Japura River (Uakti & Phillip Glass)
La Petite Fille De La Mer (Vangelis)
Fur Elise (Beethoven)
Pathetique - 1st movement (Beethoven)
Symphony No. 7 - 2nd Movement - Allegretto (Beethoven)-you will love that one
The Tempest -3rd movement (Beethoven)
Terms of Endearment (Roger Williams)
Brian's Song (Roger Williams)
Shenandoah (Floyd Cramer)
these last 2 have choir in them but they're incredible, very powerful
Requiem - 9th movement - Lacrimosa dies illa (Mozart)
Requiem - 10th movement - Hostias (Mozart)

I have just recently asked a question about things that annoy people on Y!A. A few of the responders said that they hate these sorts of questions because the people who ask the question are not really interested in what they are asking.

Is this one of those questions?

Edit:
I did not mean to be rude. My apologies.

Now if you want songs look no further than the works of Franz Schubert:

hxxp: en. wikipedia. org / wiki / Schubert_compositions_D_number_1-504

hxxp: en. wikipedia. org / wiki / Schubert_compositions_D_number_505-998

And I would also suggest the following pieces:

Mozart - Piano Concerto No. 20 in D minor (2nd movement)
Arthur Sullivan - 'The Lost Chord'
Satie - Gymnopedie No. 3
Brahms - Waltz in A-flat major, Op. 39 No. 15
Handel - Courante from Keyboard Suite No. 1
Schubert - German Dance No. 1
Schumann - Traumerei from 'Scenes from Childhood'
Marcello - Adagio from Concerto in D minor
Granados - 'The Maiden and the Nightingale' from 'Goyescas'
Purcell - Minuet from 'The Double Dealer'

That should get you started.

I have one recommendation; no piano but violins and other strings:

hxxp: www. youtube. com / watch?v=1dPDO3Tfab0

Alberich

There is no such thing as an "instrumental song" - by definition if it is instrumental it is not a song.
If you are looking for melancholy music the suggestion of Schubert is a good one. He wrote both instrumental and vocal music. Start by listening to his piano music - the impromptus and the late piano sonatas.