I have just installed a fresh copy of Ubuntu 15.04 on my laptop, however I cannot connect to my wifi. My network shows up fine, but when I try to connect it simply waits a minute trying to connect and then shows a message saying 'You have been disconnected'. Is there an easy fix for this? My wireless card is Realtek, I believe. Any advice or help would be greatly appreciated!

Edit: The following results from running the command "lspci -knn | grep Net -A2 " in terminal