Multi use Windows 7?

[Rylic234]

My friend is looking into getting his first desktop.
He needs an OS ,I have my Disk of Windows 7 OEM just wondering if he can also use it or does he have to buy one?

 

[Eduello]

One license can be used for one motherboard; Your friend needs to buy one.

 

[USAFRet]

1 license, 1 PC.
He needs to buy one for his PC.