Able to make continous music loop in Arduino and control the volume of the music with light sensor reading? I'm new to Arduino and am planning on making a simple program in Arduino that will play and loop a sound file on the computer whilst controlling the loudness of the music based on reading from a light sensor.

I was wondering if the first part, playing and looping the music on the computer is possible, because the second part of controlling the volume with the light sensor seems more straight forward if I had the first part down.

Thanks!
Having the Arduino play the audio doesn't really make sense for the scenario you describe. 

I would suggest you write an application on the PC that plays music and takes in input from and external source that is used to control the volume. You could then use the Arduino (connected via USB) to relay the light sensor readings to your PC application. The PC application then does all the "heavy lifting" since it has significantly more resources available than compared to the Arduino.