User ID matches old Macbook so i can't connect to it!

I bought a new MacBook and migrated my data to it, now i want to be able to use TEamViewer to connect to my old laptop when out of the office, but when i enter the user id of the old laptop into teamviewer on the new laptop, it says i am trying to connect to my new laptop! I read somewhere that the two computers need different hard drive names, so i changed the name on my new computer and reloaded TeamViewer, but it keeps assigning my new laptop the same user ID as the old one.  HELP!!