Well, it probably won't work. The game installation made entries into the Windows registry and may have written files to the /windows directory tree. So if you just copy the directories with the games, nothing will run.
If you have lots of free time, are bored, and don't mind the risk of ruining your new machine (you do have OS backups, right), you could try exporting all of the registry keys that seem to be associated with a given game on the old machine and loading them into the new machine's registry, then seeing if the games will run.
Personally, I recommend contacting tech support at the various game companies. If they are still in business, they may be able to help you.