I work in the Tech Bay at Best Buy and one of the most common problems is spyware, so we remove it from customers' computers. This one had over 10,000 infections in the temporary internet files and system folders alone, then over 70,000 more infections in the system restore files... by the time the scan was over, it had around 87,000 infections. Of course when you tried to remove them, it froze the computer :-(