endless reboot, even hardware reset is not happening

my tablet was working fine untill 30sept2017,

then suddenly it start getting on and off continuously.

my tablet remain on for just 1 or and half minute and work very fine during that period.

I tried to hardware reset, but that too not happening.

after hardware reset, I press system reboot and found that NO DATA was erased.

Nothing happen,

I tried to uninstall any app, first it show app uninstall, but when it get on and off next time,

the app was still working .

how is this possible?

pls provide some sollution.

service centers people are really confused and unknown about this problome.

they are giving very different-2 advices/sollutions, that too not working.