How can I bring my tab to alive

Hi,

I recently had problem in downloading and installing apps from Windows store to my Acer Iconia W701 tablet, so downloaded a firmware from Acer website and upgraded the firmware. The firmware upgrade is completed 100% within a minute and after that the tablet looks dead (black screen and nothing happens when I press power button). I tried various combinations to go to boot screen like pressing windows button + power key, volume button + power key, long press… etc. nothing works my screen is still not powered and tab looks completely dead.

can someone help me how can I bring my tab to alive.