Estimated time to complete: 10 mins

Deleting a file from your computer is like opening a book and scratching out the name of a chapter in the table of contents. The chapter isn’t really gone, just the information about how to find it is. To really wipe out the information in a book, you would turn to the chapter itself and scribble over the words until they were illegible.

When a file is deleted from your computer, the only data erased from the hard drive is a small bit of information that points to the location of the file. The actual file remains on the hard drive where it can be retrieved with common software tools.

A secure delete application such as Heidi Eraser will prevent the recovery of deleted files by overwriting the file data with meaningless data. The number of times the data is overwritten is controlled by selecting the number of passes the application employs. Securely erasing data with this procedure is considered a best practice for eliminating sensitive data, and is a critical task to perform if you donate or sell your computer.

Before You Proceed:

These Security Shorts are intended for non-technical users who manage their own computers. If your computer is managed by an IT department, do not proceed. Contact your IT administrator for further assistance.

Eraser is the recommended application to perform a secure deletion of files or disks on a Microsoft platform (Windows 95, 98, ME, NT, 2000, XP, Vista, Windows 2003 Server and DOS). This application is free, and can be downloaded from the Eraser homepage: http://www.heidi.ie/node/6.

You need administrative rights to your computer to install this software.

Step 1: Download & Install the Eraser Software

Securely Erasing Contents of the Recycle Bin

Securely Erasing Individual Files

Securely Erasing Unused Disk Space

Step 1: Download & Install the Eraser Software

1. Open your Web browser and type the following link into the address bar: http://www.heidi.ie/node/6
2. The Eraser website opens. On the front page, click the Download button next to What is Eraser?
3. On the Download Eraser page, click the Download button next to the version of Windows running on your computer. The instructions shown here are for the latest versions of Windows: Eraser 5.86a for Windows 95, 98, ME, NT 4.0, 2000, 2003, XP & Vista (32 & 64 Bit).



4. A new page from SOURCEFORGE.NET opens. Under Filename, locate and click EraserSetup32.exe.

Note:

There are various application versions available dependent upon your operating system and system architecture. For more information on 32 bit vs. 64 bit architecture, visit: http://support.microsoft.com/kb/827218



5. You may need to right-click the security toolbar and select Download File… to allow the software to download.



6. A window appears with the question Do you want to run or save this file? Click Save and save the Eraser Setup to your desktop. When the download is complete, click Close.
7. Locate the Eraser Setup icon on your desktop and double-click to open the file. A window appears with the question Do you want to run this file? Click Run. When the download is complete, click Close.
8. The InstallAware Wizard opens. The InstallAware Wizard will install Eraser on your computer. Click Next to proceed.
9. Read Important Information and click Next to proceed. Agree to the terms and conditions and click Next to proceed.
10. Select Destination Folder where the setup will install files. It’s okay to accept the default location of C:\Program Files\Eraser. Click Next.
11. Select the location where you would like to create new shortcuts. It’s okay to accept the default program folder of Eraser. Click Next.
12. A window appears with the message Completing InstallAware Wizard. Now ready to configure Eraser. Click Next to begin. An Eraser scheduler may appear. Close this window. Click Finish.
13. To check for a successful installation, locate the Recycle Bin on the desktop and right-click the icon. Eraser options should appear in the pull down menu.

Securely Erasing Contents of the Recycle Bin

1. To erase contents in the Recycle Bin, right-click on the Recycle Bin. Multiple types of Eraser methods appear on the pull down menu. Each method specifies the number of times the information is written over (aka "passes") while erasing the file.

Note:

In general, the more passes performed on the file, the larger degree of confidence that the deleted file will not be able to be recovered. The time it takes to erase the file is based upon the number of passes performed; therefore, a higher number of passes means the erase time will be longer. 35-Pass is recommended for very sensitive data.



2. Right-click on an Empty Recycle Bin and select the Eraser method with the number of passes you want.
3. A window appears with the question Do you wish to erase the contents of the Recycle Bin? Click Yes to begin overwriting the Recycle Bin contents. A window will appear showing the progress of overwriting the Recycle Bin contents.



4. When your selection has been erased, an Erasing Report will be displayed. Click Close.

Securely Erasing Individual Files

1. Right-click on the file you want to erase. Click the Erase option on the pull down menu. A window will appear with the question Are you sure you want to erase this file? Click Yes.

Note:

You can select the Options button to modify the number of “passes” to be performed on file. Selecting a higher number of passes will take longer.



2. An erasing report will appear. Click Close.

Securely Erasing Unused Disk Space

You can erase unused disk space—which could include files that have previously been deleted but have not been overwritten—that reside on your hard drive. This operation is especially useful if files containing sensitive data may have been previously deleted without being securely erased.

Securely erasing unused disk space with this procedure is considered a best practice for eliminating sensitive data, and is a critical task to perform if you donate or sell your computer.

1. Right-click on Start > Explore to open Windows Explorer.
2. Right-click on Local Disk (C:)
3. Click Erase Unused Space



4. A window appears with the question Are you sure you want to erase unused space on drive ‘C:\’? Click Yes.

   A window appears with the message Erasing: Unused disk space. Searching… In a few moments, erasing begins. Depending on the amount of data, erasing could take several hours.

5. When your selection has been erased, an erasing report will be displayed. Click Close.