You may not uninstall the program completely. Although you click the uninstall icon to uninstall the program, there still mightbe some files left. You have to clear them manually. After that, reinstall.
On your desktop, the icon of PowerDVD may still exist, you'd better delete it either. Create a new icon for PowerDVD from the folder of the program, right click the exe. file, select create shortcut to desktop. When you double click the PowerDVD shortcut on the desktop, you can open the program.