1. Click on Events on the GUI and post the error messages
2. Post mcebuddy.log (click on Logs)
It's likely that previous uninstall wasn't clean. (the service needs to be deleted after an uninstall, typically when the uninstall is not clean the next install fails to start the service with an error 1001.
Then try to install 2.3.4 (do a clean install, refer to the documentation -> Installation Issues on how to do a clean install and let me know the results)