Thank you for your message.
Regarding the issue you experienced, I recommend to configure the installation folder of PRTG ("C:\Program Files (x86)\PRTG Network Monitor\") in the whitelist of you anti-virus. Usually, anti-virus move the suspicious file in quarantine, and therefore allows you to get the file back.
If it's not the case, then I invite you to execute the installer of your version to reinstall PRTG Administrator. You will find the installer under "C:\Program Files (x86)\PRTG Network Monitor\PRTG Installer Archive". Before executing it, please stop both PRTG services under PRTG Administration Tool > Service Start/Stop to avoid any issue.
The Data folder won't be modified/removed by the installer, it will only replaces all PRTG files (and add PRTG Administrator.exe) in the installation folder.
If you have questions, let us know.