Welcome to Android Forums. Sorry for the delay in responding to your question.
Before trying to take it into service try this:
Pull battery and then hold power button down for thirty seconds. Then reinstall battery and apply power.
If still messing up go to menu/settings/privacy (or where ever your factory reset option is on your phone. Perform a factory reset.
This will wipe all user data from the phone so download AppTyrant from the PlayStore first.
When you first open it up it will save all your downloaded apps to a folder on the sd card in their .apk form.
Once the factory reset is complete then open up the PlayStore and sign in to your Google account to get your contacts back.
Go to the SD card with a good file manager like ES File Explorer. Find the AppTyrant (might be labeled Root Uninstaller) folder. Go to auto backup. Copy and paste all the .apk's onto the root of the sd card (not in any folder, just in the same directory as all the other folders).
Long press on an .apk for the install option. When done installing, select Done and install another.
Not a whole lot of traffic in your phones specific forum just yet (new phone?), but you can post in there if you have any more questions. You must register first.
Phone forum is here:
Samsung Galaxy Grand Quattro - Android Forums
I'll put that forum in my favorite section so I can check it once a day in case you need more help.
AndyOpie150
