How can trail versions recognize the expiry date even if they are deleted and reinstalled?

Answer 1

they leave records in the registry file or other locations

Answer 2

some trial versions write the current date into the code at the time they are downloaded

if the trial software came on a disc, they sometime write a special file with the date, the first time they are installed on a computer

this file is not generally deleted when the program is deleted and can be hard to find, the information may also be added to a windows configuration file that you need for other stuff to work

in these cases, you might have to completely re-install the operating system to eliminated the date stamp

my advice is to only use trial software for the legal, approved, trial period

good luck

Answer 3

I agree with everyone else; the trial software adds a registry key in to the computer's registry. I have tried a number of ways to circumvent them and, thus far, I have failed. Even if you were to do a system restore, to restore your computer to an earlier date prior to installing the software, it won't work. The registry key(s) added are not remove during the restore. You can compare the registry before installing and after installing to create a list of keys created or changed. But, there are hundreds - if not thousands- of keys, so it will be very difficult to find the key(s) responsible for disabling the software after the trial period.

Answer 4

There's an even easier way. Microsoft does it with it's Genuine Advantage scan to see if your XP is legal. The program "reads" you computer's components (motherboard, hard drive, cpu, etc.) and creates a unique, one of a kind identification number. If that number shows up on another install, the computer is denied the download. It's actually a lot easier to modify the registry (if one knows what he or she is doing) than to change out a computer's internal guts.

Answer 5

It varies depending on the program.

Some make cookies on your web browser. These will tell the website that you have already downloaded the program and won't allow it again.

Some change your registry to put restrictions agains reinstalling the program.