I've just upgraded our three PC's to V.4. Two had V.3 and one had V2.7. As recommended I uninstalled the previous versions before installing V.4 V2.7 uninstalled immediately with no problems. However both PC's with V.3 gave problems - basically the uninstall procedure "stuck" part way through, saying there were 3 seconds left. But that three seconds went on for ever with no progress and in the end I had to stop the process with Task Manager. When I went back to run the Uninstaller, it was still there and the uninstall did then complete. After restarting I deleted the ESET folders, installed V.4 and all's well. The problem arose on both computers (XP SP3) on which V.3 was installed. Although I got there eventually, it looks as if there is some basic flaw in the uninstaller.