For that I suppose you need the Mathcad activation server tot run. That was a MathSoft server. After the acquisition by PTC that server was stopped some 5 years ago...
I'm afraid you have bad luck.
What remains is that you can contact PTC support. Maybe they can help you.
I ran into the activation problem a few years back when my computer died and I bought a new computer.
I installed mathcad 14 on the new machine, then copied the mathcad 14 file folder from the old hard drive to the new hard drive to overwrite the installed copy, then I had to change the hard drive volume ID to the volume ID of the older drive. Mathcad just came up activated after that and I've had no problems.
Yes, a few years back the Mathcad Activation server from Mathsoft still ran.
A few years back it was stopped by PTC. Question is how much difference there is between a few years back and a few years back.
Then, if I'm right, Mathcad 14 was developed under PTC, Mathcad 12 is pure MathSoft (and one of the worst Mathcad releases ever).
Did/does you Mathcad 14 use FlexLM or C-Dilla for licensing?
C-Dilla does NOT run on a 64-bit OS, which the OP's new computer most probably uses.
My copy of Mathcad 14 is a PTC product. My machine is running a 64-bit O/S Windows 10, but the Mathcad install is running from the X86 folder so it's a 32 bit version.
In any case, I moved the installation three times since the initial install in 2010, once when the mother board failed and another time when the hard drive developed problems and started to become flaky. The first time I copied the folder and reset the volume ID to the original, the 2nd time I just cloned the failing drive and reset the volume ID again. The third time was when I upgraded from windows 7 to windows 10 and the upgrade changed the volume ID and I had to change it back. (Microsoft offers a free tool called VolumeID for exactly these situations.)
I was fortunate that I wrote the original volume ID in the CD box the program came in.
I conclude that your Mathcad 14 is licensed using FlexLM, and the license is tied to the Harddisk's volume ID, otherwise it would not work.
The receipt in the box says that it was purchased 8/2/2010, so it's the FlexLM version and is tied to the hard drive Volumd ID. I have 3 other versions of Mathcad (Mathcad for DOS 1986, Mathcad 2001, and Mathcad 12), but none of them are installed on any machine, the DOS version and the 2001 versions only need the 16 digit code from the CD. Mathcad 12 needs the code from the CD and then there's the activation from a Mathsoft server, which is longer supported since PTC bought them.
Believe it or not, I still use the keyboard shortcuts from the DOS version for everything. It's much faster than the drop down menus.
I did reinstall Mathcad 12 once. I had to call tech support and some woman walked me through the re-install process, which involved giving her a 16 digit code from the disk and the volume ID from the hard drive. It worked back in 2009, but I use 14 now and I don't plan to go back. My machine at work has Mathcad 15 and prime, I like 14 better than either.
I'm still a happy user of Mathcad 11, the best Mathcad there ever was😊.
(Especially because it has the largest support for Maple functions, and it works fast.)
Is Mathcad 11 still available to download, install, and activate?
Is Mathcad 11 still accessible to current users (2020)?
Or is it the luck of those who had Mathcad 11 already installed a long time ago?