I agree the 4650 is no slouch. Miles and miles better than what is on that board now. It's too bad we don't have any WoW players in here, from what I've heard from some is that if you have all the settings maxxed out things can really crap out when a million things are going on at one time on the screen. But anecdotal evidence isn't useful here so I won't put any merit in it. Pblr, would you be satisfied if the card could only smoothly run on high settings at 1680x1050, but not highest settings?
My housemate used to play WoW, but this was I believe before either expansion was released. From what he told me the game used to lag pretty badly when a large raid was taking place if he maxed out the settings, he was using an X800 back then. I would probably place the HD4650 more on par with an X1950, if not an HD2900GT, so it's twice as fast as what he had, but I don't know how much of a problem the game was - he was using 1280x1024 back then. Using 1680x1050 will need a slightly more powerful card anyway I would imagine the HD4650 could run the game maxed out at that resolution OK, but not perfectly, certainly I would say it would run fine for the most part, on high but not maximum, which should be sufficient. If pblr89 really wants, [assumption]he will almost certainly need at least an HD4670, preferably an HD4830. In this case, a new PSU is the order of the day, which for an HP almost always means a new case, i.e. a new PC. For what it's worth the CPU in that system might also prove a limiting factor, so that could be upgraded too while he's at it. I'm not sure how demanding on the CPU Wrath of the Lich King is. What I am certain of is that the GTX280 is overkill for WoW, at least with that monitor size. I'm going to assume pblr89 did not understand Shamb1es' reference to frankenstein. Assuming you do know what frankenstein's monster is, it's a joke, as running a Power supply outside the case is very messy as far as cables are concerned. It is also potentially dangerous, as it allows things to fall into the fan grille of the PSU more easily. Generally, I would not recommend this approach.