Hello,

I am writing an application that I want to give to a select number of customers.

What is the best solution to use so that after the trail period (1 month) the application will no longer work.

I was thinking that if they are interested in purchasing the software I will give them a license key or something, to unlock the application. However, I would like to make this unique to every computer.

I am have a very limited budget as I am working on my own. So is there any free 3rd party products that does this?

I was thinking of writing the date the application was installed in the system registry, and each time the application loads it will check if this date is over one month. However, the user could turn back the date on their computer.

Another, solution I was to have the application run some many times. For example, the user can only run 30 times. Then it will lock.

Many thanks for any advice,