PencilState said:
You can install any 64-bit Linux OS free.
A true upgrade.
The OEM is not obligated to provide a 64-bit version. Only retail copies of
Vista entitle one to both dvds (you can still only use one or the other, not
both.) You can purchase a retail x64 edition (the upgrade version will work
for you) but you will have to perform a clean installation of the x64 OS.
You cannot migrate from any 32-bit Windows to any 64-bit Windows by
performing an upgrade in place. Contact the OEM for what might be available
from them and what impact installing the 64-bit OS will have on your
warranty and OEM support.