brand new ipod 4 gen. bought from apple, i plug it into my laptop and it says "itunes can not cennect to the ipod because an invalid responce was received form the device" but when i plug it into my moms laptop it connects and does everything i need

are you using the latest iTunes version or at least the same or newer version than on your mom's laptop?

Error 13, 14, 35 and 50 (or -50)

These errors are typically resolved by performing one or more of the steps listed below:

1. Perform USB isolation troubleshooting, including trying a different USB port directly on the computer. See the advanced steps below for USB troubleshooting.
2. Put a USB 2.0 hub between the device and the computer.
3. Try a different USB 30-pin dock-connector cable.
4. Eliminate third-party security software conflicts.
5. There may be third-party software installed that modifies your default packet size in Windows by inserting one or more TcpWindowSize entries into your registry. Your default packet size being set incorrectly can cause this error. Contact the manufacturer of the software that installed the packet-size modification for assistance. Or, follow this article by Microsoft: How to reset Internet Protocol (TCP/IP) to reset the packet size back to the default for Windows.
6. Connect your computer directly to your Internet source, bypassing any routers, hubs, or switches. You may need to restart your computer and modem to get online.
7. Try to restore from another known-good computer and network.

iTunes cannot connect to the iPhone because an invalid response received from the device

This error occurs when there are problems communicating through USB. This may be resolved by following the steps for errors 13 or 14 above.

Have you tried to create new user on that computer and check if for the newly created user it works, to see is it software or hardware problem...