I have some software that I purchased, once I installed it I had to call the mfr. to get the actvation code which is only good for a moment in time I presume and on my machine only. I'm not using the software and would like to free up the space without losing the software. Is there any mirror method that I could use to move it to a CD and preserve the software? One problem is, I've had to download a number of updates since it was released and it would be a PITA to start over with my original CD and have to go thru the update process again, call & get an activation code etc.

Not really, not without imaging your whole machine.
But if you just copy the whole directory out of program files, or where ever it installed, and then just delete the directory, you free up the space.
The computer still thinks it is installed, you just can't use it, or any other software the uses it, till you copy it back. Leave the directory there if you need it to remember where the files go.
Make sure you check the box to keep the file structure when you burn it.

Or spend a few bucks and upgrade hd.