I'm entitled to the Student version of Photoshop CS6. Adobe has given me heartburn from day 1 by changing policies. So, to try to bridge the gap, I've repeated installed the 30 day tril of Photoshop CS6 extended. After the first use, it told me it was expired and offered to let me buy it. I uninstalled everything to do with Photoshop, even to searching the C drive for anything with Photoshop in it. I restart my computer as requested. Each time I'm expired. I even changed logins with a different host (hotmail vs yahoo), and same thing. Adobe is getting so bureaucratic and impossible, I just don't want to deal with them. I'll stick with my current editing software programs. It may take more steps and I may have to use more than one editing program, but I don't have to deal with that growing monster called ADOBE!!
And a trial is just that - it runs once for 30 days and that is that. After that you can reinstall it until your hair turns gray, but it won't come back. And messing with your system only makes things worse.