So with Vista Ultimate 64 Bit OEM version, I will have to call up Microsoft every time I reformat my computer? Or I can reformat fine as long as I have the same motherboard? Please let me know, thanks.
If you use the same hardware you can install as many times as you want. It is only if you use a new mobo and CPU. Sometimes there is a glitch and will ask you to reactivate after a video card driver update. But it will work no problem as long as you have the same mobo and cpu.