Trial version will be unusable after a period of time. When you reinstall it, it not going to work because the previous program has left some keys in your registry that will detect the same program when reinstalling. To make it full, there are many ways. Some use runasdate, time stopper... But for now I want you try the way I used to do. First, you have to clean all the keys left in your registry by using little registry cleaner after you remove the unused trial program. After that, try to reinstall it and use the time stopper afterward.
