How do enable wireless and ethenet connection in Inspiron 7420 using Ubuntu 12.04?

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http://askubuntu.com – I am beginner with Ubuntu and recently installed Ubuntu 12.04 LTS as dual booting with Windows 8. I would like to continue with Ubuntu as it is amazing. However I am straggling with internet connection. It could not be connected either the wireless nor the Ethernet. Please help in this, I have been trying for a week but no way. Thanks in advance. (HowTos)