Windows is a free operating system, as it is with the Apple Macintosh, Linux, etc. The Windows software that you use on your computer is not free and will come with a cost. For most applications you'll find a website that is free to download the application, or at least free for a trial download. This is because they want to promote their product, and get you to try out their product before you purchase it, even if it is a trial version. The program will usually be compatible with Windows, but the program may require you to have certain Windows programs installed in order to run.
The free trial allows you to try the program and see whether or not it is something you'll want to buy. If it is free then you will have no worries about whether or not the program will be able to run on your computer. The download usually only takes a few minutes and will allow you to download and install the program to your PC, where you can then try it out for the free trial. If it doesn't work then you can always buy the program and try it out for free.
