I tried McAfee as it came bundled with my Compaq had loads and loads of problems (so did lots of others on the Compaq support forum for my model) I deleted McAfee and installed Norton A-V 2000.All my problems disappeared. I have only ever been infected once(i think?) and Norton got it,caged it and i then binned it.So Norton Anti-Virus gets my vote, easy updates,scheduler and interface.