Just about every PC has confidential information that you'd really rather not share with others: user names, passwords, emails, addresses, phone numbers, credit card details and more. But getting rid of this is difficult. You can delete files, partitions, even reformat your entire hard drive, and it may still be accessible to people with the right software.
If you're about to sell a PC or hard drive, then, or you just want to be sure that deleted files are gone forever, then you need a tool like Paragon Disk Wiper 10 Professional. The program can overwrite every sector on your hard drive, or a specified partition, multiple times. Your data will be shredded to the point that no-one will be able to restore it, even with expensive data recovery hardware.
Disk Wiper can also be used on a day-to-day basis to securely wipe your hard drive's free space. This will eliminate any remnants of confidential documents that you might have just deleted, without affecting Windows, your applications or other data.
Paragon produce a cheaper Personal version of this tool, but the Professional edition does have some useful advantages. Like support for many standard disk wiping algorithms, for instance: US DoD 5220.22-M, US Navy standards NAVSO P-5239-26, British HMG Infosec Standard No.5, German VSItR Standard, Peter Gutmann's algorithm, and Bruce Schneier's algorithm.
Paragon Disk Wiper 10 Professional also includes a scripting feature, perfect for automating common tasks, and letting less knowledgeable users take advantage of the program, without the risk of them wiping their system.
Please note, this trial version of the program will let you see how it works, and the functions on offer, but these work in virtual mode only. You can't use the trial to actually wipe any files on your drive.