My opinion is to boot it up first. Make sure you didn't get a lemon before you even bother to start upgrading. Otherwise, you won't know if it is the new ram causing problems or something completely different. Just my .02 worth. Granted, if all you are doing is upgrading the RAM it may not make a difference since that swap is fairly simple. I definitely don't recommend upgrading the hard drive (I know that isn't in your current upgrade plans) until after you have had a successful boot.