I am sorry, but if you purchased through Steam, please follow the steps meant for Steam only.
For Steam Purchases:
Even after using the purge file, you still need to use the 'uninstall' option (image is for Fences but its the same for Groupy):
Then re-Install from Steam and Steam only.
Please DO NOT change any of the default settings until you verify that the application is running as expected in its default state.
Try that and report back.
Stardock Community Assistant