There is a "trick" way to avoid a reboot during installation of Tag That Photo. The reason for the re-boot is the installation of a Windows Explorer plug-in - when you right-click on any folder or images that are monitored by TTP - the plug-in makes a new menu available to perform various tasks.
The workaround is if you create a .bat file with the following lines in it:
taskkill /f /IM explorer.exe
explorer.exe
Run this (double-click on it) just before you click "uninstall TTP" when the Installer prompts you.
The batch file is also attached as a zip file.