Hi, depends what you're trying to achieve. if you just want a blank disk then using the Win98 boot floppy as electronicsfreak suggests however if you want a to completely wipe all old data from the disk so that it is unrecoverable but still be able to reuse the disk again you will need 3rd party software such as Ghost Enterprise or such. These applications write zeros and ones to all locations on the disk after wiping it thereby overwriting all your old data and essentially blowing it away. As rvnguy says, some of the manufacturers do provide disk wiping utils but again it depends on how unrecoverable you wnat the old data to be!