I don't want to buy a new OEM license each time I buy a new computer and\or motherboard ...
Why would you have to buy a new OEM license?
Also, keep this in mind: Whether OEM or Retail, a Windows license can only be installed on one computer at a time. Aside from the difference in support, the only difference between an OEM license and a Retail license, is that an OEM must stay with the computer on which it was originally installed, while a Retail license can be moved from one PC to another PC. Even so, it can only activate 1 computer at a time.
It's OK with me that I can have the retail version only on one computer at a time. lets say a steam roller accidentally rides on my PC. In OEM license the steam roller destroys my windows as well. but in the retail license, the steam roller destroys only my PC because I can re install my windows on a new PC, so I buy new PC without buying windows again.
I know it's not logic that a steam roller will ride on my PC, but just for the example (-: