Take it back to Best Buy, tell them that you're unsatisfied with the job they did, explain why, and then demand that they fix it.

Next time, I'd avoid using Geek Squad or any other similar service. You probably have no more than a 50/50 chance of someone who has even half a clue working on your system. Look around your area for computer shops, and start asking around to see how reputable they are.

Sadly, kind of like the auto repair industry, computer repair shops can sometimes be very shady. Many will install pirated software, swap out expensive components for cheaper ones, suggest repairs that are unnecessary, etc. At least one good indicator of a place to avoid, is asking if they have any problem with you being present for any and all work to be done. If they have no problems with that, it's a good sign, though it doesn't mean everything they do is above board.

If there are no local shops, or shops within a reasonable driving distance, ask friends and neighbors if maybe any of them have a kid or relative who's good with that sort of thing and might be willing to help. Odds of success are probably about as good as using a service like Geek Squad this way, but it's probably cheaper and you're helping some local kid instead of a large faceless corporation.

That's my suggestion anyway. Feel free to take it or ignore it.