What is the problem?
Have you uninstalled and run the clean script?
Or, please forgive the suspicion but you specifically mention »testing version«, are you trying to get more than your alloted 30 days of Photoshop trial?
What CP says: once you have installed a trial version, you can never re-install it on the same computer—short of deleting everything on your computer, re-formatting the hard drive, and re-installing the OS and all other applications.
Hardly a realistic proposition for most people I know.