I think jenn0123 was looking for a USB version of the hardlock due to the lack of suitable ports for the old dongle on most recent computers.
There are USB to Serial conversion devices on the market, but I would not guarantee that they would work with the old dongle (they may, but I have my doubts).
Even if you find a USB dongle, you may find that the drivers provided by DataCAD have issues with Windows 10 on your new computer: The information on DataCAD's Hardware Key Driver Update page
says that the updated drivers support Windows 2000, XP, Visa and 7 (and there has not been any update since then).
In a google groups discussion from a few years ago
Carl Steidel noted that the driver worked on his desktop running Windows 10 but not on his laptop. My own experience is that the DataCAD drivers do not work on Windows 10. In the above group thread there was discussion of alternative drivers that some found to work and may be worth investigating.
I hope you find a USB hardlock, but just be aware that you may need to also source alternate drivers or install Windows 7 on your new computer to be able to use it.