RAM - you already have more than enough. More than a Gig is overkill unless you are trying to decode the human genome. I have no idea what the max allowed for that laptop is because you didn't tell us. Go here http://www.crucial.com/ and plug in your specs.
Hard drive - NO. What you have located is a desktop drive. Go here http://www.impactcomputers.com/dellparts-dell-laptops.html and have a look at "laptop" drives. As a general rule concerning laptop drives, bring money.
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