This is on a dual boot (XP/W2K Pro) system. Trying to change my A/V solution, I've been testing NOD32 on W2K Pro (SP4) and have found that regardless of what settings I disable in the trial version of NOD32 3.0.669 that my system will hang (totally unresponsive) after a definitions update when I try to shutdown. I have to power down using the switch. The events viewer states the profile could not be unloaded. I tried UPHClean which does not resolve the problem. This is a show stopper for me, but I want to figure out the problem so I can proceed. The system shutdown/reboot is normal if I have not allowed or done a definitions update after booting up. I have looked at a number of other A/V solutions - at least the ones that still support W2K - and none showed this particular problem. I have a bare minimum of services running, only 16, and have no other A/V or firewall installed or running. My previous/current firewall is ZoneAlarm, of which I've tried all versions compatible under W2K and XP, up through 7.x which uses Kaspersky, which is a huge resource hog - the reason I am looking for a low resource solution like NOD32. Machine is based on an ASUS M2N-E SLI motherboard, 4 gig of RAM, AMD 64 X2 6400, Matrox P750 Millenium graphics card.