<A HREF="http://www.eweek.com/article2/0,1895,2032732,00.asp?kc=EWNAVEMNL101806EOAD">One in three people write down computer passwords,</A> undermining their security, and companies should look to more advanced methods, including biometrics, to ensure their systems are safe, a new study shows.A study released on Tuesday by global research firms Nucleus Research and KnowledgeStorm found companies' attempts to tighten IT security by regularly changing passwords and making them more complex by adding numbers as well as letters had no impact on security.