From the Purge reinstall steps : You need to do the purge first than do uninstall option in Steam. Than reinstall from Steam only.
For Steam Purchases:
Even after using the purge file, you still need to use the 'uninstall' option:
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.
Stardock Community Assistant