I had PE 8 and upgraded online to PE11. PE8 is showing 3.99TB in templates. I tried to uninstall PE8 but it prompts for the CD, then tries to install again. Running Win7
That should not be. Simply open the Windows Control Panel, then Programs and Features, select the program and click the uninstall button.
If for some reason your installation isn't letting you uninstall, you can just delete the program files from the Program Files directory and then clean it up with a registry cleaner.
BTW, the program could not possibly be using 4 terrabytes of space for its templates. The entire installation takes less than 700 megabytes. But you can certainly remove it if you need that space.