Flobo WipeTheDisk is the best utility you need to securely erase all traces of your activity on computer.

Deleting a file, partitioning a disk, or formatting a hard drive will not erase your data!Just run FloboWipeTheDisk and select area of your hard disk: whole partition, whole hard disk wiping process.

It erases all viruses including master boot sector viruses (if erasing hard disk is specified).