Nothing really as long as you are not running the Operating system on 2 machines at the same time. Win 7 has a new revision of Vistas Easy transfer cable the most you may need to do file and settings transfers is an external hard drive, or network connection to the new machine.
PS U cannot transfer to a new machine if u are talking about an OEM license, in order to transfer to another computer it must be a retail license. According to the terms of the licenses
October 19, 2009 12:13:33 AM
I wonder if the expertzone copy they gave is OEM or retail since it is not for resale. Its promotional.