My Sony Google TV suddenly became a brick last night, after my Sony e-reader became a brick a few months ago. It stopped responding, then I turned it off and on, it still showed the Sony logo and a few animation, after that only the bluish circle was spinning forever. I pulled off the power plug for a day, then I started googling a solution, and I found this:
1) Unplug the power cord from the Internet TV device.
2) Use a ballpoint pen to press and hold the CONNECT button on the bottom of the Internet Player.
3) Plug the power cord back into the Internet TV device.
4) When the System Recovery screen appears, release the CONNECT button.
NOTE: It make take around 30 seconds before the screen displays.
5) Press the CONNECT button once to select Factory Reset and un-pair Remote Control.
6) Press and hold the CONNECT button for just over 5 seconds.
7) Release the CONNECT button.
8) Press the CONNECT button to select Yes.
9) After choosing the desired reset option, press and hold the CONNECT button for just over 5 seconds.
10) Release the CONNECT button.
which was working for me. The device turned back to the out-of-box default setting. The only difference is in steps 5 and 9, I don’t think I did press CONNECT button for just over 5 sec, I just skipped and it still worked. I am happy. The following are where I got the tip from, and I thought Sony had taken the KB off from their website which appeared in link 1.
http://community.sony.com/t5/Internet-TV/NSZ-GS7-won-t-power-on/td-p/120239
Process Studio 
Thanks! Really worked for me.