HI ,
I have a Yamaha PSR-E333 KB. I have the USB cable also. But for the last 2-3 months m trying to record the exact piano voice into the PC since I want to upload it online. But I am failing to do so. Can some tell me in detail how could I achieve this .?
The USB connection on the PSR-E333 is a MIDI connection. It is used for transferring MIDI data and “song data” between the keyboard and a computer. It is not an “audio” connection and you cannot transfer audio (sound) from the keyboard to a computer using that USB connection. Yamaha do not make this clear in their sales literature 
, but you can find a bit more about using the USB connector in the section of the keyboard user manual in the section “Connecting a Personal Computer” (page 44).
See here for the Audacity part of the story: http://manual.audacityteam.org/man/FAQ:Recording_-_Troubleshooting#keyboards