Yep. Same here and (I guess within EULA) i bought one for a PC i built my mum.
I give her the help she needs as well.
@OP - With a OEM you will NOT be able to get support from microsoft if something happens generally like a windows issue. I am afraid its down to you to sort that problem. Apart from major issues, like stated above, you need to transfer the license. Or at least that what the T&C's say in the license.
I get mine from Amazon, cheap as chips imo.