Simply emptying the Recycle Bin doesn't trash data. Here's how to safely remove unwanted files and your web history
Given that data is invisible, it's not hard to let your PC become overrun with it. A good clear-out freshens up a PC no end, and if you're disposing of a computer there's an even better reason to clean it up.
Whether giving an old computer to charity, selling it online or passing it on to a friend, you'll want to make sure that contacts, web browsing history and your personal information isn't included in the donation. Read on to find out how to ensure that personal data is properly deleted from a hard disk.
Indestructible data
Disposing of data from a hard disk is not as simple as putting it in the Recycle Bin; the computer will erase its record of the file but the information will remain on the disk somewhere. Web browsers also store lots of important information that you might not want to share and it is advisable to delete information regularly.
Destroying data is difficult and even damaged disks can yield secrets when examined by forensics experts. There's no need to worry about electronic criminals stealing data from PCs that have been thrown away, as the process is complicated and expensive. No thief, even with the skills and equipment, would bother.
But properly erasing files and the history of websites that have been viewed on a PC is a courtesy to new owners and can improve the computer's performance.
There are two types of data that need deleting: internet files and saved data. With the former, regular scheduled computer maintenance should be carried out, as this improves your computer's efficiency. Saved data deletion needs different techniques and special tools, but you can download a free utility from our website, which we will get to shortly.
This should be done before giving away a computer or to destroy sensitive documents. First we'll discuss some of the issues to consider and then explain how to erase data beyond any practical use.
To delete data safely from a disk, it helps to understand how it gets there in the first place. The heart of a hard-disk is the platter, a set of highly polished plates, split into smaller compartments called sectors, that spin at speeds approaching 200mph.
Data is stored on the disc magnetically, so you don't lose everything when you shut down the power. A read/write head, which looks like the arm of a record player, moves over the disk and writes information onto each platter. Every time data is written to the disk, a record is kept of the part of the platter on which it has been stored.
When you put a file in the Recycle Bin, the file itself isn't erased; Windows merely discards its record of where the data was stored. As you continue to use the disk, the computer will eventually overwrite the original data you stored with new information.
But think of your hard-disk as a large library. All the books are numbered and their location stored on a card file. If the card file was destroyed, a search through every volume would need to be carried out to find a particular book. But they would all be where you had left them - on the shelves.
Covering web tracks
Modern web browsers store a myriad of information about an individual's internet use, most of it kept to save time and bandwidth when accessing favourite sites. The code and graphics that make up all the sites recently visited are stored. So when passing on a computer, this is an important point to consider.
For your own use, deleting information is worth doing because it will make the computer more efficient. Neglecting to clean up the browser once in a while can cost a lot of storage space, slow down internet access and make the computer more prone to crashing.
Luckily, Windows has a few simple tools that enable you to clear the browser quickly. Every time a web page is visited, it takes a little while to download all the images on it. These images aren't meant to be stored for a long time because they'd take up too much space, so Windows stores them in a folder called Temporary Internet Files.
This is useful if you're visiting particular sites on a regular basis because already having the images saves on bandwidth. The Temporary Internet Files folder should be cleared out from time to time, though, as it can grow to a surprisingly large size after a long period of internet use.
One of the most pernicious forms of web data storage is the use of cookies. Many websites store small text files on your computer when you view them, and these can be very useful, for storing login information to sites that require registration.
But some cookies also record web viewing habits and send reports back to their owners. It's not quite as cloak-and-dagger as it sounds, because the information is mostly used to target advertising and the means of collecting it is included in the terms and conditions of respectable websites.
However, it may also slow down the browser. Deleting all the cookies is an option, but you will have to re-enter usernames and passwords on sites that require them.
The web page history is another file you might want to remove. When a web address is typed into the browser, it is saved and will appear when you begin to type it into the address window again. Also, when Internet Explorer's History button to the left of the address line is clicked (a circular clock icon with a green arrow pointing backwards), a record of the websites you have viewed will be displayed.
The pages that have been visited are stored in folders filed by date - clicking the links within the folders will take you straight to the page. History can be very convenient for reaching websites that are often visited, but it also provides a list of your web habits to anyone else using the computer.
Internet Explorer can also remember other information that is typed into the browser. A function in Windows called Autocomplete will save particular information you put on forms. Type in the first few letters and suggestions based on previous visits to the web page will drop down. This is designed as a time-saving measure but has the unfortunate side effect of displaying a whole host of personal information.
The big clear-out
When deleting any web information, the first thing to check is that you're not online; there's no point clearing the files if a web page is adding new ones at the same time. Shut down all other programs as well. Open Internet Explorer, go to the Tools menu in the top toolbar and select Internet Options. The new window will display the General tab and this provides the quickest way to delete your data.
In the central box there is a button labelled Delete Files. Click on this, check the box to delete all offline content and click OK. Regular internet users should do this once a month, but if you want to limit the amount of space the folder can use, click on the Settings button in the central panel. You can also specify when the temporary files are updated, but this is best left on automatic setting.
This panel is also useful for editing cookies. On the opening screen of the Internet Options panel is a Delete Cookies button but this dumps the whole file indiscriminately. The View Files button under Settings shows all cookies that are stored on the disk, which then enables you to select which ones to dump.
Removing the record of websites visited is a simple affair. Under the General tab, click the Clear History button. To deal with the Autocomplete function, click on the Content tab in the Internet Options panel. The Autocomplete button opens a window that allows you to delete all form information and passwords, as well as deciding when to switch off the function by clicking Clear Forms.
It's also possible to instruct Internet Explorer not to offer the option of saving passwords. Users of shared PCs who don't want to accidentally save website passwords should ensure that the 'Prompt me to save passwords' box is unchecked.
Rewriting history
Files stored on a hard-disk are more difficult to remove permanently. As we've explained, simply putting a file in the recycling bin doesn't delete it but just makes it more difficult to find. All those files can still be read using a few simple internet tools.
To destroy this kind of data, special software is needed that can find uncatalogued pieces of information and overwrite them with random data, thus making it almost impossible to read. This is often done repeatedly to ensure that the original data is unrecoverable, even by experts.
These tools are most commonly used by businesses that might be targeted by data thieves, but it's also a good idea to clean up home computers in this way if you're donating the computer to a friend or charity. There's no need to pay if you use Eraser.
Click the Free Download button. Choose the nearest location and then click the red and white icon on the right-hand side to download Eraser to the Desktop. Double-click the icon to unzip it and then double-click the Eraser Setup icon to install and launch the application.
Once activated, there are a variety of ways to overwrite deleted files. For now, let's simply delete all uncatalogued files on a PC. Select New Task from the File menu and click on the drop-down menu arrow under the option marked 'Unused space on drive'. Choose Local Disk C from the list that appears and then click OK. The hard-disk will now appear in the list in the main window, so single-click to highlight it and then select Run Task from the task menu.
A warning will appear that it is not possible to recover data that is overwritten, so if you're sure that everything you have emptied from the Recycle Bin is no longer needed, click OK to begin.
Note that the process takes quite a long time, because the program must first round up deleted files on the disk and then write over each file six times. The amount of time it takes will depend on the size of the hard-disk and the amount of deleted files to be erased, but don't plan to do this at the last minute before handing the PC over as it could entail many hours. The PC can be left to its own devices during this time.
The final stage after any deletion is to defragment your hard drive. This is a process that shifts data held in disparate disk sectors closer together so that the reader head can access it more quickly, with the added effect of overwriting your newly-deleted files and making the PC faster.
Go to the Start menu and choose All Programs, then Accessories and then System Tools. Select the Disk Defragmenter and click on the Analyse button in the bottom left. The computer will look at the hard-disk and proceed if needed. We recommend that all PC users defrag their hard-disk about once a month.
You've got mail
Just as putting items in the recycle bin doesn't automatically delete them, putting emails in Outlook and Outlook Express into the Deleted Items folder doesn't automatically get rid of them either. You can bypass the Deleted Items folder by pressing Shift as you delete the email, or by right-clicking on the email and choosing Delete from the menu.
With Outlook Express go to the Tools menu at the top of your screen and choose Options, then click on the Maintenance tab. At the top of this screen you should check the box for 'Empty messages from the Deleted Items folder.'
Click on the Clean-up Now button. This allows you to either compact your stored emails, delete them and the header information they retain or even try and retrieve that information.
With Outlook it's possible to configure the software to delete all emails when you shut down. Go to the Tools menu, then Options. Go to the Other tab. Select the Empty the Deleted Items folder and click the check box.
Safe and sound
While organised gangs of data thieves may be targeting big companies to steal information, they don't really bother with home PCs as the pickings are relatively small. But deleting your data is important, particularly if passing on the computer to someone else.
While there's little fear of having your personal data hijacked for nefarious purposes, it's only polite to take your data off an old computer. The new user will want to build up their own store of personal data, and if the browser is constantly trying to put your personal details into web pages, it makes annoying surfing for the new user and is a security risk for you.
Deleting data not only secures privacy but helps make the computer run better, saves storage space and, most importantly, makes sure you are in control of what's seen and what's not.
Source: http://www.pcmag.co.uk
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