The only way to "sanitize" an old drive is to overwrite
every magnetic bit on the disk.
If you're serious about security, start with multiple overwrites, using software that conforms to Department of Defense specifications.
Some utilities let you overwrite files multiple times with patterns of ones and zeroes, but computer forensic software may still recover them if the method used isn't strong enough.
Once the e-mail has been auto- deleted, the system overwrites
it so that it cannot be undeleted.
Low level formatting, which refers to overwriting below the level of the operating system, is not as effective as overwriting with utilities programs because it only overwrites once and with a single pattern; the more overwrites that can be done the less likely it is that the data underneath can be recovered.
But if the floppy drive or tape drive that overwrites the data is aligned differently from the drive that originally wrote it, data may be relatively easy to recover with special software or altered drives.
a Even after you delete a file and empty your trash or recycle bin, the data remains on your hard drive until another piece of data overwrites
The company has also released a new version of BlackBoard FileWipe, its 32-bit utility which overwrites
files up to ten times with random data to prevent data recovery from deleted files.
If you're not sure whether your device has the virus, here's a quick way to check set the Hot Sync Manager to Desktop Overwrite