When you download a paid or shareware program, the manufacturer always offers a "trial" version to download from their site. The trial version, in most cases, is the real program complete with all its features even if after a few days it will stop working.
This number of days, which can vary from program to program, is a trial period of the product at the end of which the user will decide whether or not to buy it or not.
To cheat the trial and extend the trial period, you could change your computer's time or, more reasonably, change the run date for that program.
An innocent little utility for Windows, which needs no installation, allows to run any program by setting the date and time at will.
In practice RunAsDate he's able to fool software protection making him believe it is a different date than that of the system when running a program. The system date is not altered, only the executable can be fooled at will. Technically, the utility intercepts the GetSystemTime, GetLocalTime, GetSystemTimeAsFileTime kernel calls and replaces them with a date and time decided by the user. RunAsDate is not infallible, I very much doubt that all programs are fooled by this little program, however, before proceeding to uninstall the program or looking for a crack, it could be a quick and easy way to use RunAsDate.
Alternatively, if this doesn't work well, you can extend the trial period of a trial program with the tool Time Stopper which creates an icon on the desktop of the selected program with a locked mode, ie it does not spend the time available for testing the shareware trial software. I don't know if it also works with antivirus, but I think not.
It can also be change the internal Windows date with the program Beyondo which allows you to change the day, month and year on the system calendar. This way you can also send emails making them look like something from the past. To return to the current date just do a reset from the same tool.