Phone [Q] Sprint Galaxy Nexus-Transfer Issues

Hello, Not sure if this is a nooby question. But, I've been playing around with roms for a while. Right now, im using the SlimKat rom on my Galaxy nexus ( version 4.4.2. Slim version: I was trying to change roms today. I went through the usual stuff. Factory reseting the phone and deleting the cache. When i went to transfer the files for the new rom to my phone from my PC i get an error that says " Cannot copy item The device has either stopped responding or has been disconnected". I can delete things on my phone from my computer and take files off the phone, but it wont let me put files on. After thinking it was the rom, i went to the toolkit to try to install the stock rom. This also didnt work. Any tips?