You have to decide whether it's cheaper to acquire an upgrade for that package (if available), or get WinXP license and install it into a virtual machine inside Win7 where you can install and use it. In case your Win7 is Pro version, WinXP license is included in the form of "XP Mode".
Yes, we have purchased Key Creator which is the update for Cadkey. We have this one instructor who insists on using Cadkey. thanks for your input.