Touchscreen almost completely unresponsive.

Hi all

Just got my Nexus 7 brand new and I can't get past the set up process as the screen is behaving very bizarrely. I'm at the wi-fi settings section and the screen is just going mad... it's like someone has remote control of it and is clicking in and out of various networks available to me and typing random password attempts. As i watch the keyboard I can see the keys "pressing themselves". When I try to type it doesn't register my touch at all.

So at the moment it's completely unusable and I can't even get it to power off!

Anyone come across anything like this/got any ideas?

With thanks

Gg