Q: trying to sync new music to ipod...says invalid response from device ??

Hello The Hat32,

I understand that you are having an issue syncing your iPod touch with iTunes on your PC. Let's go over some general troubleshooting to get that sorted out. 

What I would start with is looking at any security software that is on your PC. This can prevent both devices from communicating with each other and could present that error. Another ting is to also the USB connection. If you can, try a different cable or USB port on your PC to see if that fixes it. 

Take a look a the articles below to go over in details on resolving conflicts with security software as well as additional USB troubleshooting options. 

Resolve issues between iTunes and third-party security software
https://support.apple.com/en-us/HT201413

Resolve USB-related alerts in iTunes
https://support.apple.com/en-us/HT201413​

Take it easy