Only way to recover your tablet is by doing hard reset remember by doing this your installed apps will be deleted:
Letís get started:
1.press and hold the power button + volume up at the
same time. This will get you into recovery
2.when android logo appear, release all the buttons
3.use volume keys to select and power button to accept
4.Choose wipe data/factory reset
5.reboot your device
Press ThanKs If I HelPed YoU...!
First of all you canít install any custom rom without root access !!!
And if you want to root your device install framaroot but it will not work as you mentioned that the tab is not starting up, So can you plz upload some SS so that i can understand the whole story from beginning
Sent from my GT-S5360 Using tapatalk 2
PreSS ThanKs If i HelPeD YoU ?!?