Sorry this is rather a longwinded post, but please bear with me.

Got my second Nexus7 yesterday - the first one suffered the dead pixel issue.
When I went through the setup procedure I couldn’t log into my Google account, got the message ’Not able to establish a stable connection to the server’ despite being connected with ’excellent’ signal strength and 54Mbps speed. I tried again on a different connection, this time whizzing  through the setup and all working as it should. However on going back to my own connection I was able to surf  the internet, but none of the Google services worked. I changed channels on my router several times but nothing seemed to make any difference, until I disabled security and then, Bingo! I had a fully functioning tablet.
Unfortunately resolving one issue has presented me with another. I now have an open network, and a tablet that wont fully connect to a secured network.
Can anyone tell me what’s wrong please?