I am a computer systems analyst and I have to disagree with your assessment on the Geek Squad. However, I do see why you would be upset. Boycotting or telling others not to take their computer to a place that you had a bad experience from is expected when you had such a bad experience but I'm a bit concerned about the service that you have received. It seems that there may be a more underlying issue that they may not have been aware of when you brought the computer to them in the first place.
Did you give them all the information that they needed to diagnose the issue? Did you inform them of your activities with the computer? Did you get on a questionable website that may have affected your performance?
These questions may not have been asked by the Geek Squad, but sometimes, like with cars, if the person doing the service isn't aware of these issues, they will continue to happen without their knowledge. Surfing the internet alone, viruses, trojans and adware bombards the computer the moment you click on the browser to start it up. What you should also be aware that by legal standards, like mechanics, the Geek Squad is not authorized to fix any issues without the permission of the customer. With this said, if they found an issue, it should be documented. If there are none, there is nothing to worry about.
Exactly what was the issue to begin with and when did it start?