The problem seems to only occur if a new release is installed over an earlier release. The file: C:\program files\malware defender\MDservice.exe, must be removed before installing a new release. Actually the MD installer should remove it during the install process, but the current release (1.1.2) does not do that. Workaround: COPY the folder C:\program files\malware defender\, to your desktop. Some files will not copy, that's OK. Uninstall MD, and reboot. Go to the folder C:\program files\malware defender\, and delete MDservice.exe. Lastly copy all the files in the new folder on your desktop back to C:\program files\malware defender\, and install the new version. Runs very well now with Low CPU usage.