Need help - Nano v2 not seen by Win7/64 PC

There is little that could fail in USB circuit. You should check R22, R23, R24. Check for shorts. Check for opens on D- and D+ and STM32. Check for 3V to the right of R24. Check if the connector pins bent. If all checks out, then its the STM32.

Look at code.google.com/p/dsonano/downlo … f&can=2&q=