i unplugged it during the system update and now no connection to tv. i have tried everything still is not working. i dont know what to do
Unfortunately, but by unplugging during the update you have now bricked your Wii U, which will mean having to call Nintendo's 1-800-255-3700 (6 am ~ 7 pm Pacific, everyday) Customer Service number to set up a repair, sorry.
you might want to call nintendo at 1-800-255-3700.