You can use Duplicate Sweeper to find and remove duplicate files stored in your Google Drive storage.
To do this, you'll firstly need to ensure that your PC is synced with your Google Drive account. Download and install the Google Drive app from here https://www.google.com/drive/download/.
The installer will take you through the necessary steps that you need to do to complete the install on your computer. Once the install is complete, the setup Wizard will open automatically. The Wizard will prompt you to enter your Google account information.
At the end of the Wizard, click Done. Google Drive will now be active on your computer, and will have created a folder called Google Drive. This folder will contain all of your synced data from your Google Drive Storage account.
Now we can get on with scanning for duplicates in Google Drive.
Launch Duplicate Sweeper and click Add Folder. If you'd like to scan your entire Google Drive for duplicates, select the Google Drive folder (by default, this is located in your user folder area). Alternatively, you can find this folder in Windows File Explorer, and drag and drop it into Duplicate Sweeper. Click OK to add the folder.
Now click the "Start Duplicate Search" button in the top-right corner of Duplicate Sweeper.
Duplicate Sweeper will now scan the folder and return a list of any duplicate files it has found. Tick the files in each group that you wish to remove, or press the "Keep All Newest Files" to automatically select the oldest files to remove. More selection preferences can be found under the Duplicates tab of the Duplicate Sweeper toolbar.
Also our Duplicate Sweeper tutorial video, which goes through the steps of finding and removing duplicates using Duplicate Sweeper.