This is the 2nd prelude from book 2 of Johann Sebastian Bach's Well Tempered Clavier, also known as the 48 Preludes and Fugues. Bach's Preludes and Fugues come in matched pairs in the same key, and are often (though not always) played as a pair in the order Prelude first and then Fugure. Here is the corresponding Fugue for this Prelude also in the key of C minor, and together the prelude-fugue pair are catalogued as BWV 871.
Although there are some easier preludes and fugues in the set, much of Bach's Well-Tempered Clavier is quite challenging to play. However the complete set has for a long time been considered a must for any serious student of piano. Some other preludes and fugues from the set are available on mfiles if you check the Bach page or Classical Sheet Music page. If you have aspirations to be a good classical pianist then we recommend getting the complete Well-Tempered Clavier which comes in two books. Here are links on "sheet music plus" to Book 1 and Book 2 of the Well-Tempered Clavier.
The audio controls below allow you to play the mp3 version of Bach's Prelude No.2 in C minor from Book 2 or you can download the MP3 file. You can also download the midi version of Bach's Prelude No.2 in C minor from Book 2 or alternatively edit/play the midi file.
The image below is the first page of the sheet music, and here you can download the full sheet music for Bach's Prelude No.2 from book 2 in PDF format.