airplay does not work

I bought a new ATV3. It connected well to my Wifi and can see all the icons and could play the trailer for Life of Pi. However I have following issues;

1. ATV does not fully display on my 55 inch Panasonic Plasma HDTV.

2. Doesn't connect to any of the computers on homeshare_I did turn it on in iTunes on my PCs and on ATV3

3. Airplay doesn't work on ipad3 or iphone 4. I have updated softwares on all devicses (ATV/ipad, iphone). All are logged in with same Apple ID_

please help me.