Yes the legacy value is there, not matter what you do, trust me, all angles have been covered, you will not be able to install another evaluation version.
Anyway, suppose it was possible with the batch file, you would again be stucked with the same problem again and damage you system.
Evaluation versions are to be used once for you to appreciate the product, make your opinion on it. If you like it, you purchase it, if you don't, you uninstall it.
You tried it once, now you want to try it free again and again.
That is contrary to Kioskea's Charter.
No more help can be provided to you.
I will request for this thread to be marked as solved and closed for further writable.