As above. I tried alot of the solutions i found in the forum but have had no success. Sorry i'm a bit of a newbie with linux!!
I have that same laptop and had the same problem:
If it doesn't work, open a terminal by opening the Dash and typing
Restart computer.(The change only take place when you restart.) Thanks to our friend Karl for this.
protected by Community♦ Feb 27 '13 at 4:49
Thank you for your interest in this question.
Because it has attracted low-quality answers, posting an answer now requires 10 reputation on this site.
Would you like to answer one of these unanswered questions instead?