Installation of NOD32 V4 renders a Thinkpad T41 (Vista Ultimate SP1, 4 GB ram, 120 GB disk) useless - the machine either hangs on the user log in window or during user start-up. Specifically, the mouse pointer moves but the Start button does not respond nor is the task manager accessible (Ctrl+Alt+Delete). The mouse pointer changes to the "working" circle when positioned over the task bar. The machine does show intermittent disk activity. The machine worked without issue with NOD32 V3.0.642.0 installed. -- I did not perform the initial installation. I subsequently uninstalled V4 in Safe Mode (via the program group icon) and reinstalled it (process repeated twice). Both subsequent installs performed using the Windows Administrator id. -- I have disable logging (the setting prior to the first installation) in the ThinkVantage AccessConnections manager. -- I have not performed a manual uninstall of NOD32. Any such process which carries the warning "this process will cause all network settings (static IP, default gateway, subnet mask, wireless settings, etc.) to be lost" should be considered an embarrassment to the author(s). -- I have not attempted the diagnostic steps -- msconfig, disable start-up processes one-at-a-time, reboot after each change -- to determine where a conflict might exist. If one is found, what will be Eset's response, "unistall the conflicting program"? I would find such a response unacceptable. I run NOD32 on 3 machines, 2 others have already been upgraded to V4 (neither running Vista). Luckily I had a current image and data backups so nothing was lost except 5 hours of diagnostic and restore time. If I cannot resolve this issue I will be forced to pursue a refund and find another antivirus solution. Does anyone have any ideas or guidance?