将回答的问题包括：如何永久删除文件、猫和电脑共处以及大型文件夹备份等。
问：我想把我那台旧的戴尔电脑捐给慈善机构，但我不希望我以前的任何文件和信息会被看到或被恢复。我怎样做才能确保这一点？一个朋友告诉我仅仅删除这些文件是不行的。
答：你的朋友说的是对的。在Windows操作系统下用标准方式删除文件，只是向操作系统发出指令：可以重新使用被删除文件所占用的空间。文件的内容，或者其中的一部份，可能永久地保留在硬盘上，除非有别的文件将它覆盖。
为了确保你的硬盘不被别人窥探，你必须用无用的数据将那些文件覆盖，甚至包括未占用的空间，最好反复进行多次操作。这个工作可以通过一种名为“文件清洗程序”的特殊应用软件来完成。例如Webroot Software (网址：webroot.com)开发的软件Window Washer就是这种程序，当然还有很多其他程序。
问：我的猫喜欢卧在我的个人电脑上，或者蜷伏在电脑旁边。这样对于我的电脑和我的猫有什么危险么？
答：你的猫可能没问题，但如果猫挡住了电脑的通风口，或者过多的猫毛进入电脑，你的电脑可能就出问题了。你应该避免让你的宠物挡住电脑通风口和风扇，它们都在电脑的后部。你最好定期检查通风口，确保它没有受阻，以保证空气自由地流通。另外，你偶尔也要打开电脑，清理积落在电脑内部元件里的猫毛。
问：我那台装有Windows系统的个人电脑已经用了3年，里面的照片文件夹最大可达500 MB。我有一个用于文件备份的驱动器Iomega Zip，但对于这么大字节的文件夹而言，它实在是太小了，难以有效地完成备份工作。你对备份这么大的文件夹有何建议？
答：我建议你使用一个能刻录的CD。那种能刻录一次的单片CD光盘成本不足1美元，但能轻而易举地完全容纳下你的文件夹。如果你的个人电脑上没有安装CD刻录机，即所谓的CD-RW驱动器，那么你可以买一个可添加的刻录机。有些刻录机是内部安装的，有些则是外部安装，通过USB端口连结。任何一种刻录机的价格都超不过200美元。
How to Wipe the Slate Clean; Cats and Computers Coexist
By WALTER S. MOSSBERG
There’s no other major item most of us own that is as confusing, unpredictable and unreliable as our personal computers. Everybody has questions about them, and we aim to help.
Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability. This week my mailbox contained questions about permanently erasing files, cats and computers, and backing up large folders.
If you have a question, send it to me at
mossberg@wsj.com, and I may select it to be answered here in Mossberg’s Mailbox.
Q: I want to give my old Dell computer to charity, but I don’t want any of my old files and other information to be visible or retrievable. How can I be sure of this? A friend says that simply deleting the files won’t do the trick.
A: Your friend is right. Deleting files in the standard way in Windows merely instructs the operating system that the space occupied by the file can now be reused. The contents of the file, or part of it, may remain on the hard disk forever unless something is written over it.
To be sure that your hard disk is safe from prying eyes, you have to overwrite the files, and even the free space, with nonsense data, preferably multiple times. This can be accomplished with a special kind of utility called a file-wiping program. One example is a program called Window Washer from Webroot Software (webroot.com), but there are many others.
Q: My cat likes to lounge on top of my PC, or curl up next to it. Is this a danger for either the computer or the cat?
A: The cat’s probably fine, but the computer can suffer if the cat blocks the cooling vents, or too much cat hair gets inside. You should keep the pet from blocking the vents and the fan, at the rear of the PC. You should check the vents periodically, and make sure they’re clear so air can flow freely. You might also open the computer once in a while to clear off any cat hair that has accumulated on internal components.
Q: My pictures folder on my three-year-old Windows PC is up to 500 megabytes in size. I have an Iomega Zip drive for backups, but it’s really too small to back up this folder efficiently. What do you recommend for backing up a folder this size?
A: I suggest you use a recordable CD. A single CD-R disc, which can be written upon once, can easily hold the entire folder, and costs under a dollar. If your PC lacks a CD recorder, called a CD-RW drive, you can buy an add-on model. Some of these install internally, while others are external and connect through the USB port. Either type can be bought for less than $200.
