1) Using the client locate where the configuration store and backup store locations and note them for later cleanup.
2) Uninstall any GPOADmin clients. There is no way to track where they are installed.
3) Stop and Uninstall any GPOADmin Server services and GPOADmin Watcher services.
a. These services may be located using the following AD query for GPOADmin 5.8+
The DNs in this list will show the locations of all Servers and Watcher services.
4) Remove any backups from the backup store location.
5) Remove the configuration store. This requires connecting to the configuration partition noted in step one (AD or AD LDS) and removing everything under CN=Configuration…, CN=Services,CN=Quest,CN=QGPM.