Well i have buy for windows 8 - is upgrade from 7.
But now on clean windows 8 install is done - is ask for a new licens ( for clean install and cant use my opgrade key )
Crap WINDOWS LICENS - is on same PC on SAME HARDDISK - but just Clean install vs OLD Windows 7 + 8 Licens.
Install from your external hard disk. 32 bit to 64 bit :-)
You shall do this. 100 % work.
( when your not have any DVD burner or USB key - This work:-) )
Install Windows 8.0 clean and new install from any External hard disk maket by old from 32 bit system to 64 bit
( YOU NEED )...