Norton Navapsvc.exe or McAfee VS are Hogs!! They eat 98% CPU time and computer resource. It's not the anti virus program at fault! Look at the source i.e. the Internet browser. Tighten security first! thru the security options in browser properties. By selecting the default settings to begin with, magically releases your cpu from the constant virus scanning your auto protection has to perform. The barrage of info coming from the outside world the browser is allowing, makes the anti virus auto protect device (or applet) scanning all the time. I hope this helps a lot of people. This applies to Win98, WinMe, Win2K, WinXP, Win2003, Win2K3 using McAfee or Norton anti virus.

There's more to it than that. Symantec acknowledges a problem, sometimes NAVPSVC.exe will use 50% to 90% of the cpu, when nothing is going on. They have an elaborate list of things to do, mainly to tie you up. I went thru them, never found the problem, but it went away. Now, it's back, which brings me here. I did set IE6's security to default, but it did no good.