I don't know enough what type of chipset your player has.
Is your player's screen still stuck on the "rebulding library" message or after you've done the reset, you can get into the menu?
The shorting of the pins and getting your player into adfu mode really applies mainly with Actions chipset players. I'm thinking yours is different but can only really find that out by either the "firmware version/info" screen on your player or by opening up and posting the chip/board ID numbers.
Try downloading this:
Download Chip Genius V3.01.0613 - MyMPx
See if that helps determine the chipset of your player.
Also, have you tried a DIFFERENT USB just in case the issue is with a faulty USB cable which means your computer can't detect it.