I'm having some virus problems with my MacBook. This morning my computer started honking repeatedly and telling me that I have viruses and then I started to get pornographic websites showing up one after the other. I immediately purchased online and installed Kaspersky 2011 Anti-Virus and it is doing a "full scan" as I write this, but I'm still getting the porn websites. How can I block these and what else should I be doing? I'm running Mac OS 10.5.8, 2.2 GHz Intel Core 2 Duo, 4 GB 667 MHz DDR2 SDRAM. Thanks.