Do you know the name of the utility?

This may be a bit technical but unless your hard drive has multiple partitions then it would be impossible to reformat the drive and then reinstall the operating system because the act of formatting would erase the files required to reinstall your operating system. If there are multiple partitions then a complete format would be possible. I still believe that the files are so big, (18 megs, and three files at 5 megs), that they haven't only been around since 3/24. If that were the case then these files would fill the hard drive completely thus making your computer unusable within a relatively short time unless they were purged regularly. Furthermore, there are several hundred instances of malware being intercepted or removed in the 152 kilobyte portion of the file you sent me. That would imply an "infection" rate on a daily basis in the hundreds or even thousands if the file had only been created on or after 3/24.

If I had to place money on when the file was created I would bet an awful lot, (without having seen the files), that they were created long before 3/24.