Hi Shatty,
the handling of your Net Express license is independent from your Windows version.
So, install Net Express 5.1 on the new computer in this way:
At first Wrappack 6 (full installation) and after that Wrappack 8 if you wish, but better the latest Wrappack 13.
Explanation: Wrappacks are cumulative and include the contents of the previous Wrappacks.
Handling of your license in few words:
You have to free your old computer from the Net Express license, that's generate a Revoke Key. Very important: make a note of this Revoke Key! On the new computer you have to generate a Request Key. Login to the Micro Focus Supportline website and with both Keys you can request Micro Focus to send you a new licence key. choose: De-Activate / Activate my Product ( Revoke / Request Keys )
You will get a email with the new key and enter it on the new computer.
For a full description have a look at:
supportline.microfocus.com/.../revokerequest_help.asp
Regards, Torsten