The PinUP System installer is a fairly 'simple' installer for your windows. It mainly just copies files into locations and registers some of the comobjects. (it doesn't add any 3rd party libraries to system, or mess with your .net versions or stuff like that).
with a full PinUP Install here are the locations of files (default locations).
c:\PinUpSystem : main root folder of PinUP System. Contains all executables and settings for your PinUP System.
c:\visual pinball\VPinMame: location of PinUP Player driver for VPINMAME. Allows use of PuPCapture tables for interactive videos. Also will copy PUPDMDControl.exe for hardware dmd support in Popper Menu.
c:\visual pinball\tables\plugins : You will find the PuPlayer B2S Folder. This is part of the PinUp Player B2S interface for PuP-Packs.
watch a great video Terry did for locations as well: https://www.youtube.com/watch?v=kVrYB5wFtWU
Make sure you exit all apps and ensure all PuP and other game programs are closed completely.
you can run the uninstall from windows on PinUP Player.
check the above locations for extra files that you can delete manually if needed.
NOTE: The PinUP Installer DOES copy a version of Freezy/PUP dmddevice.dll into your VPINMAME folder. To restore you can look in your VPINMAME folder and there should be a 'pupbackup' folder. this is the original files it overwrote on your system during last install of PinUP. You can copy those files back to vpinmame root to get your system back to original.
Also, if you just manually/overwrite dmddevice.dll in your vpinmame and DO NOT want to use PuPCapture. Make sure you check and modify the dmddevice.ini file under the heading [video] you set enabled=false