Data destroyer

[laissez-faire]

What utility can I use that will remove traces of deleted files on the hard disk? About to give away a computer and have deleted all files but would prefer to make sure they are properly destroyed! Thanks chaps!

 

[laissez-faire]

What utility can I use that doesn't totally wipe the HDD though - I have not got time to format the disk and reinstall everything. Just looking for something that churns up the 'empty' space on the disk.