Hmmmm,

The theory is simple, when the executable is run the first thing it does is check the system date to see if a predefined time has been reached. This is the sort of stuff that licence checking software does.

This can be done in two basic ways:

1. Check for elapsed days since first activation (so you would need to store and increment that)
2. Check for a predetermined date.

Counting the number of times a program has been run is also simple, once again you need to store the result and increment it.

Neither approach is likely to be effective against someone who is determined to cheat you.

Let's face it, if it were easy to defend intellectual property there wouldn't be all those "warez" and "crackz" sites, would there?