How do I enforce an expiration date for a trial install of my software?

Question

I need to offer a trial period for my custom software. I have a 64-bit C# app, which uses 64-bit, multi-processor support DLLs. Other utilities to be included are written in C++

Answer 1

How can it be stored in a way as to be unrecoverable? Registry entries and files can be deleted. Alternate data streams don't get coppied into a zip file, so if you know the file that contains the ADS that contains the install data of the software (which is being used to reference the the current time to calculate days since install), you can just compress it in a zip file then extract it again and byebye to the install date reference. Store it as raw data on the harddrive (not referenced in the File Allocation Table as a file) and it will be overwritten when a file is saved to that location on the harddrive.

So I literally can't see a way to make an impossible to remove trial install date for copyprotection. It just can't be done.