OK when I upgraded 100+ systems to .657 a couple months ago, 5 systems exhibited the "100% CPU/Impossible to use computer unless ekern is disabled" problem. The systems had very little in common other than they were all running XP. I booted in safe mode, and ran the uninstall via the start-->eset menu (it works in safe mode even though the Windows installer is off, Add/Remove won't work). Go into C:\Docs & settings\all users\application data and delete the eset folder. Go into Program Files and delete the Eset folder. Use a good registry tool (I like "Reg Organizer") to search and destroy Eset and NOD32 entries (won't be many). I then used Reg Organizer's auto repair, which mostly just finds dead links (missing files, folders, keys) and deletes the registry entries. Lots of similar utils out there to choose from. Rebooted, reinstalled .657 They've ran like a dream since. This also solved other strange problems I had been hearing about a couple of these systems (ie: intermittent long logins). Hope this helps.