[Arjun Acharyya]

The service warranty of my Tab has expired on January of this year, and now, surprisingly, all the apps are crashing on launch (even the default android apps like gmail, play store etc. and settings too). I have successfully performed hard reset on it for 4-5 times till now but the issue persists.
I am not willing to visit the Service center rather I am looking forward to reinstall the android 4.4.4 on my Tab.

[B. Diddy]

Welcome to Android Central! Try booting into Safe Mode, which temporarily disables all 3rd party apps. On most Android devices, while powered on, press and hold Power until the Power Off menu appears. Press and hold the Power Off selection until the Safe Mode prompt appears. Tap OK.

If the problem disappears in Safe Mode, then something you installed is causing the problem. You may have to uninstall apps one by one until the problem disappears. If the problem persists in Safe Mode, then it's more likely to be a hardware or firmware problem.