Individuals may also purchase OEM "system-builder" licenses for personal use (to include virtual hardware), or for sale/resale on PCs which they build. Per Microsoft’s EULA regarding PC manufacturers and system-builder OEM licenses, the product key is tied to the PC motherboard which it is initially installed on, and there is "typically" no transferring the key between PCs afterward. This is in contrast to retail keys, which may be transferred, provided they are only activated on one PC at a time. A significant hardware change will trigger a reactivation notice, just as with retail.