Alas, the memory advisor on www.crucial.com in an alphabetical list of HP models has nothing between "Presario" and "Professional". So no "Probook".
So you might have to check the manual about what type of memory it has and what's the maximum amount.
Luckily, I understand it now has 4 GB and for most people that's enough.
Has intel Pentium. Have 2GB of DDR3 laying around i want to see if i can give this to a friend.