Hello there, my sister seem to be having some problems with her Macbook Air. She is unable to connect to wifi and login as administrator. When any program needs administration rights she needs to input a username and a password. Whenever she inputs her username and password it doesn't login even though the codes are right. She can even login on Icloud and there it does work. it's almost like her account doesn't exist on her Macbook. When she got the Macbook she was administrator but then just 2 months ago it started having that problem. She also can't connect to wi-fi. She says it kind of jumps between working and not working. It may work for a week and then it can stop working for a month or two. She has tried connecting to our router directly and just restarting the internet over and over again. She is able to connect to all other routers except ours. It may be her AVG security or her firewall or something like that, that is blocking our wi-fi but to turn off her AVG she needs administration rights. And she doesn't have that. Please help you magnificent geeks 
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