"Can files be undeleted by an undelete utility? Will Complete Cleanup prevent anyone from undeleting the internet files?"

Complete Cleanup has a "no undelete" feature. There are programs found throughout the internet which will allow anyone to recover a previously deleted file, but if you turn on the "No Undelete" feature of Complete Cleanup, anytime someone recovers the files you have deleted, it will only return garbage in the file, and not the actual data. This is one of the nice features of Complete Cleanup which can be turned on or off at anytime, without seeing any slow down in the software performance. Simply click the "On" button under "CC Settings" where it says "File Wipe/No Undelete" if you wish to turn this feature on.