Hi,[QUOTE=jc836;2250276]Legal answer is it depends on if it is an OEM copy or the “full version.” [/quote] No difference here. For each computer, a separate license is needed.
This is different to some MS Office products: MS Office Home&Student can be installed on up to three computers (under certain conditions I am not aware of).
If you are concerned that you will need to install on several machines-then get a multi-user pack of the OS ( more money but completely legal for the number of machines).
System Builder versions are often sold as 3 or 5 pack. (seen them at Amazon)