Re: my tablet wont come on less than month since i got it batt fully charged
I would attempt to force a soft reset (reboot). Ways of doing so varies from device to device but it usually involves pressing and holding power or volume buttons separately or together for a few seconds or longer for the device to reboot/soft reset.
That is about all I can suggest if your sure the battery is charged/plugged in. Otherwise sounds like a hardware failure of some sort. If the device is new, exercise your warranty options.