Copy the license file ("license.xbin", e.g.) from your old computer to a diskette (floppy disk) or usb-stick.
The license file is normally in the directory C:\Program Files\jv16 PowerTools 2008 or something like that.
Copy the same file from the diskette or usb-stick to the main directory where you have installed jv16 PowerTools on your new PC, normally C:\Program Files\jv16 PowerTools 2008 or something like that.