i have original window inbuilt with my laptop, i have recovery cds too.
Quick answer, yes you can load your Windows 8 on to your new harddrive. Windows that is normally loaded onto a PC by the manufacturer, is normally an OEM licence. That means it is tied to be used on that PC only. Fortunately Microsoft's defines the motherboard as being the PC, so normally you can replace/upgrade RAM, graphics cards and of course hard drives.
I believe a one off only like for like repla cement of the motherboard can also be made if you call Microsoft support.