Installed the new and 'improved' 4.x NOD32 Anti-virus client on three machines yesterday. All three machines experienced problems with explorer.exe hanging. Explorer.exe not responding and also very slow to respond. Manually removed all traces of 4.x because I don't have the time to troubleshoot this issue, re-installed 3.0.684 and everything is back to normal. Running Windows XP SP3, fully patched on all three machines. Deleted the install file for 4.x and will hold off for now. I'm getting the feeling this release was rushed, no?