You've asked a million dollar question lol. Even HP's site doesn't specify. It does look like it comes with one 4GB stick, with another slot open, so at the minimum, it'll handle 8GB. It "might" do two 8GB sticks, but I doubt it.
If you like my post, or solution to your issue/question, go ahead and click on the little star by my name and/or accept the post as the Solution. It makes me happy.
I'm NOT an employee of Best Buy, or Geek Squad, though I did work as an Agent for a year 5 years ago. None of my posts are to be taken as the official stance that Best Buy will take on your situation. My advice is just that, advice. Unfortunately, that's the bad luck of any electronic, there's going to be bad Apples... wait that's a horrible pun.