Browsing some Sites extremelly slow

Windows XP Pro in Desktop PC with ADSL conncetion. Install Norton Security 2004, SpyBot Search and Destroy (last)and Java pluggin and after that, browsing sites like Yahoo become extremelly slow, others sites not. Unninstall all mentioned softwares, but nothing change. I am not using the Host file, but anywhere there ius nothing about Yahoo, just 127.0.0.1. Reinstall all again and the same. I can surf any other site fine, only Yahoo is slow. Any ideas?
Thanks!!