1. Find your own Oracle12C installation directory, general installation directory is D: \ app \ u01 \ product \ 12.1.0 \ dbhome_1 \ deinstall, double-click the file deintall.dat uninstall.
2. wait a long time. Enter a carriage return after the following content appears.
3. Press Enter the following content appears, some people here may vary, in short, follow the prompts to uninstall step by step.
4. Press ENTER to continue.
Or 5. Press Enter.
6. Finally just need to be patient to be all right.