I managed to consistently make XP bluescreen with NAV2004 installed just by right-clicking a folder in Explorer. If I disabled NAV, the machine worked perfectly fine. With NAV 2005, I got BSODs caused by SYMIDS.SYS up to 6 times a day. The instant I disabled NAV's "worm protection", the problem went away. This is on IBM workstations. 2 of my coworkers have machines identical to mine, and they're all seeing BSODs with NAV installed. We tried NAV 2003, 2004 and 2005. They all cause BSODs sooner or later, and the files blamed by the BSOD all point to some Symantec component.