I see the application is available on the Google Play Store which means it could be possible to remove it, but if it's attached to the operating system as a pre-installed app, then the only way to stop it is through the Recovery. This procedure will delete all the contacts, images (in some cases), custom apps and settings. To do it, turn off the phone then press Volume UP key + Power Key for 10 seconds until the Recovery mode appears. Select Wipe Data/Factory Reset and continue with the procedure by restarting the phone. It will clear the password and the items above. Once the phone starts working, go to Settings > Applications > All tab > Leo Privacy Guard > Disable and Force Stop.
