An infected laptop gave hackers access to computer systems at a Harrisburg, Pennsylvania, water treatment plant earlier this month. <A HREF="http://www.infoworld.com/article/06/11/01/HNhackwatersystem_1.html">The plant's systems were accessed</A> in early October after an employee's laptop computer was compromised via the Internet, and then used as an entry point to install a computer virus and spyware on the plant's computer system, according to a report by ABC News.