You should first check with HP and see if they have an "update" option available for that laptop. The advantage of using their update version is that it will come with the right drivers
. It's also likely to be less expensive than going out and purchasing a retail copy. And finally, if they (as they did with laptops that were NOT upgradeable to Windows 7) indicate that yours is NOT a candidate for upgrade -- I would think seriously about NOT upgrading it -- as that generally means that one or more devices will not work well after the upgrade.