Ridding your computer of personal data is an essential step before letting the system leave your possession. Recyclers and refurbishers usually wipe hard drives clean before sending them on. However, for your own peace of mind, you should permanently delete your data yourself.
Deleting the files and emptying the recycle bin is not enough. When you delete a file from a hard drive, the operating system only deletes the information that describes where the file is located. Restoring data after a file is deleted is relatively easy, even for non-experts. Overwriting the data with random zeros and ones is not good enough either. Nor is reformatting the hard drive. Expert hackers can usually restore data even after the drive has been overwritten or reformatted.
The good news is there are relatively simple, permanent data erasing solutions available and some of them are free. These software utilities permanently remove files from your hard drive without leaving any trace data that could be used to restore them. In general, this is done by writing random characters and binary data to the drive anywhere from three to more than 30 times. These utilities will cover your digital tracks as completely as possible.
Even if you think you don't have any secret or personal files, you should still run an erasing application before donating your computer. Remember that critical information such as passwords are stored on your hard drive. You may not know these hidden files are there, but a resourceful identity thief may know exactly where to look and what to look for.
Erasing utilities are available from several sources. Microsoft has provided a list of these applications on its Web page about donating computer equipment. Be sure to allow plenty of time for the erasure process, particularly if you decide to use the most complete method. After all, writing data to the drive more than 30 times can take a while.
Donating your old computer to charity helps people in need, keeps dangerous stuff out of landfills, improves your mood and might even put some dollars in your pocket. You won't get a better deal than that.